Spring preview: Offense

Northwestern opens spring practice on Saturday with as many holes to fill as it has had in recent memory.
Gone are many of the names that dominated Wildcat football over the last couple seasons -- names such as Persa and Peters and Mabin and Ebert. Into their shoes will step talented, young players who, for the most part, have yet to prove themselves at the college level.
To get you ready for spring ball, WildcatReport takes a look at some questions facing on offense and defense that will begin to be answered over the next month and a half. First up: the offense.
Will Simien and Colter continue to platoon at QB?
Colter will be the starter from Day One, and rightly so. The rising junior filled in admirably last season when the departed Dan Persa struggled to recover from an Achilles injury, completing 67 percent of his passes for 673 yards, six touchdowns and just one interception. He eventually became an integral part of the offense as a spot-duty, Wildcat QB after Persa came back.
Although Colter had no trouble running the offense, there are questions as to whether he can make all the necessary throws consistently enough throughout the course of an entire season to be the every-down guy.
Colter tore his labrum as a senior at Cherry Creek High School, an injury which likely caused Stanford to turn him away despite the fact that he committed to the Cardinal. The shoulder has healed, but there were times last season where it seemed as if he lacked the arm strength to make long throws, or ones that required more velocity.
With this in mind, offensive coordinator Mick McCall may continue to use sophomore-to-be Trevor Siemian in certain situations. Siemian showcased his strong arm and pocket mobility in limited action last season, throwing for 256 yards and three touchdowns.
Just because Siemian is under center, however, doesn't mean Colter will be on the sidelines. Colter led the Wildcats in rushing attempts (135) and yards (654) last season and excelled as a receiver, recording 466 yards and three touchdowns. Colter said after the Meineke Car Care of Texas Bowl that his receiving days were over, but we will see this spring if McCall continues to line him up in other spots when Siemian is taking snaps.
The other wild card in the mix is Zack Oliver, who looked promising running the scout team in practice, possessing a big body, a big arm and more running ability than most would think.
Siemian and Oliver may play roles in 2012, but this will still be Colter's offense.
Who will fill out the depth chart at running back behind Green?
Jacob Schmidt graduated, Mike Trumpy is sidelined with an injury and Adonis Smith transferred, leaving Northwestern with a backfield of Treyvon Green, one runner who has yet to carry the ball in a college game (Jordan Perkins) and two walkons (Tim Hanrahan and Tyris Jones). Unfortunately for the Wildcats, prize recruit Malin Jones won't arrive until the fall.
Green played a significant role as a true freshman last season, rushing for 362 yards and four touchdowns, so the increased reps will further his development. Perkins, who redshirted last year, will also get a chance to show what he can do. The other guy to keep an eye on here is Venric Mark. He may line up more often at running back and less at wide receiver as McCall looks for ways to get the explosive speedster involved in the offense.
Green will be the starter this spring, but expect Perkins and Mark to get plenty of carries. Next fall, Jones may get on the field, if not the starting lineup, right away, especially if Trumpy is not healthy.
Who will replace Ebert and Dunsmore as the top receiving targets?
Drake Dunsmore and Jeremy Ebert combined to give the Wildcats more than 1,500 receiving yards and 17 TDs in 2011. That's a big hole to fill, but NU has the firepower to do it.
Chances are that two wideouts will fill their shoes, as there doesn't appear to be another superback like Dunsmore on the roster.
Demetrius Fields is the frontrunner to fill in for Ebert as the Cats' go-to receiver. The rising senior possession receiver recorded 382 receiving yards and three touchdowns in his impressive 2011 campaign, which was highlighted by a 7-reception, 73-yard performance in the Meineke Car Care of Texas Bowl.
The other leader will probably be Christian Jones. Although used sparingly as a true freshman last season, Jones has great size at 6-foot-3 and 225 pounds, and frequently demonstrated the ability to beat defensive backs on jump balls downfield.
Three other guys to watch are Mark, Rashad Lawrence and Tony Jones, who sat out last season but is one of the fastest Wildcats on the roster.
As far as superbacks go, sophomore John Plasenciawill most likely step into Dunsmore's role as the receiving thread, while Jack Konopka will reprise his role as the big superback who blocks and occasionally goes out for a pass. It's doubtful that either will be nearly the offensive weapon that Dunsmore was last season.
Who will step up on the offensive line to replace Netter and Ben Burkett?
The Wildcats' pass protection woes were on full display on New Year's Eve in Houston, as Texas A & M recorded eight sacks and constantly gave chase to Persa and Colter. Without left tackle Al Netter and guard Ben Burkett, two four-year stalwarts who started the last 104 NU games together, pass protection could become even more of an issue in 2012.
It will be interesting to see what happens at Netter's left tackle spot. Paul Jorgensen was Netter's backup last season, and the sophomore-to-be has drawn rave reviews in practice over the last two years. Patrick Ward, the starter at right tackle last season, may switch over to the left side, and another guy to keep an eye on is Shane Mertz, a player who stood out in practice last season as a true freshman. If Ward makes the move, fifth-year-senior-to-be Chuck Porcelli is ready to make a contribution, as well.
Junior Neal Deiters is the favorite to replace Burkett at right guard, but it will be interesting to see if young guns like Matt Frazier or Geoff Mogus are ready to challenge for playing time.
The other two spots on the line are set in stone: Brandon Vitabile will start at center and Brian Mulroe at left guard.
How much will the offense change under Colter?
Colter is the Wildcats' most athletic quarterback since Randy Walker implemented the spread offense in 2000. Persa was a dynamic athlete, but Colter is on a different level. While NU will likely continue to be a pass-heavy offense, McCall will adjust to Colter's strengths and weaknesses. The result: a more balanced attack with more designed runs and unconventional formations.
You can expect to see more of the pistol and wildcat sets, which will allow Colter to make plays in space. The read option fits Colter's skill set, but the Cats lack the strong stable of running backs needed to make that work on a consistent basis.
With Jones, Lawrence, and Fields, the Cats have a trio of receivers who can make plays downfield. But with Colter's suspect arm strength, deep passes may be reserved for the strong-armed Siemian. The Colter-run offense will likely consist of short passes and designed runs.
Of course, Persa did much of the same things during his two injury-shortened seasons as the starter. But Persa -- the NCAA career leader in completion percentage -- had the ability to fit the ball into tight windows. Colter is yet to show that he can make those throws consistently.
McCall will make tweaks, but expect to see the same kind of up-tempo, spread attack witnessed under Persa. Northwestern's offense may look more like the ones McCall ran at Bowling Green, when he had athletic quarterbacks like Josh Harris and Omar Jacobs running the show.