Unfortunately for Michigan football coach Rich Rodriguez, former Wolverine defensive end Brandon Graham had no choice after last season but to depart Ann Arbor for a bigger and better career in the NFL.

And with the 13th pick in the first round of the 2010 NFL Draft, the Philadelphia Eagles’ pick created a massive black hole on the Wolverines’ defensive line.

Which begs the most obvious question of Michigan’s off-season: How will Rodriguez even come close to replacing the production of one of the country’s most dominant ends?

The short answer — he won’t.

There’s simply not enough talent on the defensive front to replace a gamechanger like Graham. But does that mean all is lost in the trenches for Michigan’s 2010 season? Absolutely not.

What Graham brought to the lineup, more so than any Wolverines since LaMarr Woodley or Mark Messner, was the ability to disrupt the quarterback — something that is epically important as college football programs look to the air more and more.

It sure doesn’t help that Michigan’s defensive back corps will be even more anemic with the loss of cornerback Donovan Warren. So now, the Wolverines have no choice but to find some other way to rush the quarterback.

At first glance, sophomore hybrid end/linebacker Craig Roh seems to be the obvious choice. Playing opposite of Graham last season (technically at the linebacker spot), Roh looked solid in big-time games last year as a freshman, recording 10 tackles (two for loss) combined against Ohio State and Penn State.

As a senior at Chapparal High School in Arizona, Roh recorded 16.5 sacks, but his rawness was a notable concern. Now, with a season under his belt and a freshman All-America bid to boot, this year could be Roh’s coming out party.

Roh’s potential is clearly the most attractive replacement for Graham’s vacancy as defensive stalwart, but redshirt junior Ryan Van Bergen may be the most practical choice to fill the gaping hole.

With most of his time at defensive tackle last season, Van Bergen finished second on the team in sacks (five) and made some huge plays, including returning a fumble recovery for a touchdown against Wisconsin. Van Bergen will likely shift out to Graham’s old position, so the pressure may be on him more than anyone up front to come into his own this season.

The most interesting battles for time on the defensive line this summer, however, will most likely take place on the interior as a handful of different players battle for what Rodriguez and defensive coordinator Greg Robinson have all but assured will be a platoon.

Mike Martin is the proven leader of the defensive interior, and he should have little problem getting into the backfield and stopping the Big Ten’s best ball carriers in their tracks. In the second half of last season, Martin amped up his performance in the trenches, registering a combined 21 tackles in the Wolverines’ final three games, with one sack on Buckeye quarterback Terrelle Pryor.

There’s little question whether Martin will show up this season, probably on his way to one of the All-Big Ten teams, but sophomore Will Campbell remains an enormous question mark on Michigan’s line. The five-star from Cass Tech is a monster on the line, providing a run-stuffing complement to Mike Martin’s backfield disruptor role.

But he disappeared in most games last year, and his learning curve was, at some points, in question. This year, though, after adjusting to the college game at the technical level, Campbell should be ready. If he’s not, senior Greg Banks, who many of the coaches have talked about as an emerging leader, will absolutely be ready to take his spot. Banks knows that Graham’s leadership needs to be replaced, and judging by Banks’ demeanor after the spring game, he’s ready to step into that role.

Overall, the unit shouldn’t suffer as much as it would seem without Graham, assuming everyone steps up their game from last year. But there’s no replacing No. 55, and the Wolverines may be missing him more as the season wears on.

Preseason Grade: B-

Projected Starters: Craig Roh, Mike Martin, Ryan Van Bergen, Will Campbell

Surprise player: Greg Banks