A couple of rhyming rookie running backs and unheralded tight ends highlight the offensive side of Week 15’s Rookie Report, while a couple of Day 2 cornerbacks struggled with increase playing time on defense. Strong performances are very important for rookies at this time of the year, whether their team is heading for the playoffs or the top five in next May’s draft. Chris Tripodi will break down what he saw from select first-year players this week and how their performances may affect their evaluation heading into the offseason.

Eddie Lacy (RB-GB)

The top running back on Draft Insider’s board before April’s draft, Lacy has been the top rookie runner at the NFL level so far this season. As the only first-year back over 1,000 yards through 15 weeks, Lacy has proven his skills as a runner weren’t just a product of a dominant offensive line at Alabama. A great combination of patience, burst and power has made Lacy effective even with opposing defenses focusing on stopping him with Aaron Rodgers out of the lineup.

Lacy had five runs of 10-plus yards against a Cowboys defense that hasn’t stopped anybody of late, finishing with 141 rushing yards on 21 carries. His 60-yard run on the first play of the third quarter gave Green Bay momentum after being down 26-3 at the half. Lacy showed enough speed through the hole to get beyond the second level but his lack of breakaway speed led to him being caught from behind before he reached the end zone. Lacy’s other big runs were similar as he waited for his blocks to develop before planting and exploding through the hole, running violently enough to carry tacklers while showing enough agility to make a second quick cut for a few extra yards.

Lacy did have a bad drop early on a 3rd-and-1 pass that could have picked up a first down and had a few big losses, which were more a product of his line allowing quick penetration that he couldn’t avoid in the backfield. He did get Matt Flynn knocked down once but that was the first time all season he allowed his quarterback to get hit as Lacy has played well in all facets, pass blocking included. As long as he can stay healthy at the NFL level with his hard-charging style, Lacy should give Green Bay the multi-faceted offense they’ve been lacking in recent seasons.

Zac Stacy (RB-StL)

Since taking over as the Rams’ starter in Week 5, Stacy is a big reason the Rams are sitting at 6-8 despite losing starting quarterback Sam Bradford to a season-ending injury. After two slow weeks against the solid run defenses of San Francisco and Arizona, the fifth-round pick from Vanderbilt ripped off 133 yards on the ground with a touchdown on 28 carries and added 10 yards on his only reception of the day as the Rams beat the Saints by double digits.

While Stacy didn’t have as many 10-plus yard runs as Lacy above, his best two runs came off right tackle and went for 29 yards and a 40-yard touchdown. On the first run, Stacy didn’t panic and bounce his run outside when the hole didn’t flash, instead waiting for his blocks to clear and hurdling his own lineman on the ground. Stacy didn’t lose momentum after hitting the ground and was able to pick up another 20 yards. On his touchdown run, he showed patience again before cutting inside the block of his pulling guard, running through an ankle tackle and displaying enough speed to destroy safety Malcolm Jenkins’ angle on his way into the end zone.

Much like Lacy, Stacy is no burner but has enough speed to be successful, which he showed on a late dump off pass when he beat Curtis Lofton to the edge after the catch to get the first down. Despite his fifth-round draft status, Stacy has easily been a top-5 rookie runner in an impressive class and a huge steal for the Rams. While Coach Jeff Fisher still hasn’t committed to Stacy long term, it would be difficult to imagine a scenario in which the Rams bring in another running back via the draft or free agency if Stacy continues his strong play. Despite rushing for just 4 yards in the team’s first four games, Stacy seems likely to crack 1,000 yards on the ground with 854 over his past 10 games.

Tim Wright (TE-TB)

Wright emerged a few weeks into the season out of nowhere as an undrafted former wide receiver in college. His Rutgers connection to Greg Schiano likely got him a shot on the roster but his play during the season has proven he belongs at the NFL level, although he’s been inconsistent. In 11 games since seeing his playing increase in Week 4, Wright has five games with 5 or more receptions and five games with 2 of fewer catches. Part of that can also be attributed to playing with a rookie quarterback in Mike Glennon who has had his share of inconsistencies himself as well as game flow, as Wright tends to see more action when the Bucs have to throw more.

Wright went over 75 yards for the third time this touchdown (7 receptions, 82 yards) but scored a touchdown for the first time in any of those three games. He got behind Donte Whitner over the middle of the field and made an easy catch running wide open in the end zone for a 24-yard score. His longest play of the game was 26-yard pass late in the second quarter where Wright looked back and, when he saw Glennon scrambling, broke off his deep route to come back to the ball and put Tampa Bay in field goal range. His other receptions were all between four and seven yards and besides those two big plays, he was generally just a safety valve for Glennon as he has been all season.

At just 6’4, 220 pounds, Wright struggles as a run blocker and has been more effective split off the line of scrimmage. He still needs work sharpening his route running, which would help him use his frame and athleticism to be a tougher target to defend. Wright did well to recognize a blitzer off his edge on one play and looked right back to Glennon on the hot read, keeping the Bucs in field goal range when a sack would have taken them out of it. Wright has been needed as a starter this season and while he’s played admirably, he needs to elevate his game even more to project as much more than an ideal backup in the NFL.

Ryan Griffin (TE-Hou)

With Owen Daniels still sidelined due to injury and backup Garrett Graham joining him in the trainer’s room, Griffin had an opportunity to start for a Texans team in full evaluation mode heading into the offseason. The sixth-round pick out of UConn caught all 6 of the passes thrown his way for 62 yards and showed some potential in the process.

Griffin’s longest reception of the day came on a post where the rookie beat Antoine Bethea to the inside. Despite Bethea playing Griffin’s inside eye, a sharp cut to the post allowed Griffin to get in front of Bethea and make himself a target for Case Keenum. The solid routes he showed in college were on display on his second catch of the game as well, as he quickly reversed field off of a well-covered crossing route to flash open underneath. Griffin also showed a nice knack for finding the soft spot in the Colts’ zone coverages and did well to hang onto the ball once he was hit.

Neither Daniels nor Graham are locks to suit up in Week 16 or even Week 17 for that matter, giving Griffin a potential opportunity to force his way into Houston’s plan at tight end next season. With Graham hitting free agency and Daniels aging and injury-prone, strong performances from Griffin over the next two games could affect the team’s offseason decision making. Interim coach Wade Phillips made it a point to say Griffin’s blocking needs to improve after this week’s game, which unfortunately isn’t the strongest aspect of his game.

Sylvester Williams (DT-Den)

After starting for the first time in his career against the Titans in Week 14, Williams found himself back in the lineup for the second straight week against San Diego last Thursday night. Playing a career-high 45 snaps, the first time he’s cracked 40 all season, Williams had his best game as a pro with 5 tackles (3 solo) and his first career sack.

His sack came when Williams used good leverage and lower body strength to push Jeromey Clary into the backfield and force Philip Rivers to step up. Williams didn’t duck his head to push Clary and saw Rivers trying to sneak by, grabbing him easily for a short sack. Williams held his ground well in the run game as well and was in on a few assisted tackles on short gains. He got blown off the ball once by Clary but got lucky when Ryan Mathews slammed right into him for an easy tackle.

Williams has been a disappointment so far during his rookie season, as the late first-round pick hasn’t been able to make much of an impact on Denver’s interior line. His conditioning was an issue at North Carolina and doesn’t seem significantly improved almost a year into his career. He’s strong and athletic and if Denver can get him on the field for even 65-70 percent of their defensive snaps, he has enough upside to develop into a good NFL player.

Vince Williams (LB-Pit)

When Larry Foote went down in Week 1 with a season-ending injury, Kion Wilson got the first crack at filling in on defense. Wilson struggled and was recently cut, but Williams has started all but one game for the Steelers since Week 4. While the sixth-round rookie from Florida State struggled himself in his first three career starts, he has played well since despite not putting up huge tackle numbers. Williams did put up a career-high 6 solo tackles against the Bengals and consistently made plays around the line of scrimmage.

Williams’ biggest play of the game came on the Bengals’ first drive, as he stuffed Giovani Bernard on a 3rd-and-1 run up the middle. Williams didn’t get clean penetration and took a couple false steps, but still found his way into the backfield to make an early statement. Pittsburgh went on to score two plays later after a fumbled punt deep in Cincinnati territory. Williams also showed confidence and aggression taking on Jermaine Gresham after a short catch. Gresham stopped short to get Williams to overpursue, but the rookie went straight for him with a solid hit to stop the tight end for a short gain.

The first drive of the game wasn’t the only instance where Williams stuffed Bernard in a big spot, as the linebacker kept Bernard out of the end zone later in the game on 2nd-and-goal from the 4-yard line. The Bengals eventually scored but at that point Pittsburgh still led 30-14. While Foote will be back next season presumably healthy, a strong showing from Williams to close out the season may keep him ahead of Foote on the depth chart heading into 2014.

Robert Alford (CB-Atl)

A second-round pick from Southeastern Louisiana, Alford has seen inconsistent playing time for most of the season behind Asante Samuel, Robert McClain and fellow rookie Desmond Trufant. With Atlanta looking towards the future late in the season, Alford has started the Falcons’ last two games to give Atlanta three rookie starters in the defensive backfield with Trufant and Zeke Motta. While his debut last week against Green Bay went well, this Sunday was a rude awakening for Alford who struggled in coverage, particularly against Aldrick Robinson.

In the second quarter, Alford let Robinson run right past him on a play-action pass that went for 62 yards. Alford had already bit hard on a play action fake at the end of the first quarter that allowed Fred Davis to get behind him for a 23-yard touchdown. The rookie allowed another touchdown late in the game to Santana Moss that would have resulted in overtime had the Redskins not gone for two and missed the conversion. Alford got caught up in a crossing route while Moss went to the flat and by the time the rookie could recover, Kirk Cousins had already found Moss for the score.

Tentative all game and slow to react, Alford had serious issues against the Redskins. Targeted nine times by Cousins, Alford allowed a reception on all nine of the passes for 139 yards and 2 touchdowns. His impressive tackle numbers on the game were solely a result of him allowing completions and making plays afterwards. Instincts and reaction time were issues with Alford on tape, but his 4.35 speed helped to cover them up playing at the small-school level. Alford’s speed isn’t covering for him anymore and the Falcons will need him to step up heading into next season if their defense has any chance to improve from its dismal 2013 performance.

Will Davis (CB-Mia)

A third-round pick from Utah State, Davis is a very good athlete who needed some time to develop like Alford and most other small-school defensive backs. After playing just 13 snaps this year all coming in a Week 13 blowout of the Jets, Joe Philbin was quoted as saying both he and second-round pick Jamar Taylor were ready for more playing time. When Nolan Carroll left Sunday’s game with a knee injury, Davis had his chance to contribute and played 51 defensive snaps.

The results were definitely not what Philbin and the coaching staff were hoping to see from Davis as he struggled to cover Julian Edelman, Danny Amendola and Austin Collie in the second half. Davis allowed 7 receptions for 90 yards and while he came up well to shut those receivers down from yards after the catch, 6 of those 7 catches allowed turned into first downs. Davis was slow reacting out of the receivers’ breaks and generally gave too much cushion, allowing slants and crosses underneath for easy completions.

Davis finished with 7 tackles for the day but none in the run game. He did show good closing speed on a crossing route to Collie but between starting 8 yards off the line on 3rd-and-6 and not reading Collie’s break quickly enough, it wasn’t enough to get him to the ball. Once Brent Grimes left with a groin injury as well, former 49ers practice squad cornerback Michael Thomas entered and made a huge pass breakup on the final drive before sealing the game with an interception. Even if Carroll or Grimes misses another week, it could be Thomas who gets the first shot to fill the nickel role. If both can’t play, Davis will be pressed into duty but will get to face fellow rookie E.J. Manuel instead of future Hall of Famer Tom Brady, which could help him bounce back to a degree.

Chris Tripodi has been writing for Draft Insider since 2009, contributing Rookie Reports and Draft Reviews and interviewing NFL prospects. He also writes for Optimum Scouting, Yahoo! and Jets 101 and has previously worked at ESPN. Follow him on Twitter and check out his blog at http://christripodisports.blogspot.com.