ANN ARBOR, Mich. -- Michigan coach Brady Hoke will kick off his second spring in charge of the program, looking at how his largest players can fill the biggest voids.

"There's some obvious holes that we need to fill on our defensive line with three seniors graduating and when you look at our offensive line," Hoke said Friday, the day before the Wolverines' first spring practice.

Michigan is losing five seniors from last season: Mike Martin, Ryan Van Bergen and Will Heininger on the defensive line; center David Molk and right tackle Mark Huyge on the other side of the ball.

One player, offensive lineman Rocko Khoury, who potentially could've competed for a job, will not be in the mix.

Hoke said Khoury, long snapper George Morales, reserve running back Mike Cox and Terrence Robinson have decided to leave the team, adding they made the decision. Hoke said they each will graduate this spring and can transfer, using their final season of eligibility at another school that has a master's degree Michigan doesn't offer.

Ricky Barnum will get the first chance to replace Molk, an All-American center, while Elliott Mealer and Michael Schofield will have every opportunity play a larger role on the offensive line.

Defensive lineman Will Campbell, who came to Michigan as a highly touted prospect, might finally live up to his potential with production on the field. Hoke said the spring will be "big" for Campbell.

"He's made great progress," Hoke said. "What he's done from a physical standpoint and how he looks and with his leadership."

Richard Ash and Quinton Washington are among leading candidates to move to the top of the depth chart on the defensive line. Hoke said he doesn't have enough bodies on the roster -- especially on the lines -- to play a true spring game on April 14 in the Big House.

"It will probably be a lot like last year," Hoke said.

Hoke's first spring concluded with what was basically a practice open to the public at Michigan Stadium.