Tuesday's winter workout at Michigan State was an easy day for the coaching staff. Most of the Spartan assistants quietly stalked the outer edge of conditioning drills or watched with crossed arms as their players took over control.

Two-thirds of the way through their version of the dreaded annual college football tradition of winter conditioning, Mark Dantonio and the rest of the Michigan State coaches like to hand the reins to the team's new leaders. Players from each position group direct teammates through the circuit of sprints, jumps and other creative, torturous tests of fitness and toughness. Afterward, the group leaders are responsible for grading each individual on the day's work. Coaches hope this format creates accountability on a roster that has to replace several influential veterans this spring.

"We obviously lost some key guys, some crucial guys in that senior class," said quarterback Connor Cook. "But like every other year, you lose some guys and other guys step up."

Cook had the option to be one of those crucial losses if he wanted to jump into the NFL draft. Instead, he decided to return for a fifth season in East Lansing where he will be an important part of the leadership on an offense that needs to replace its top running back and top wide receiver.

Rather than preparing for the NFL scouting combine and pro Day events during February, Cook buried himself in old game film to find parts of his game to improve this offseason. He said he wants to improve his pocket presence, throw better on the run and look to his backs more often in the passing game. All three can help the Spartans' offense next fall and make Cook a more NFL-ready quarterback for this time next year.

Cook said he scrambled too often in 2014 when he could have stepped up in the pocket to buy himself time or dish the ball to an open running back.

"You see stuff that goes on in the NFL. Those guys make a living throwing to their back," he said. "I feel that's what we need to do here as an offense. There were so many times watching film when Jeremy Langford was wide open running free and I try to run or do something with my feet. If I just dump it down to him, even if it's third-and-12, he can get the first down if he gets the ball. That frustrated me."

Keeping himself from getting flustered will be at the top of agenda next week when Cook spends his spring break in California working with quarterback specialist George Whitfield. It will be the senior's fourth time working with the popular and unorthodox Whitfield since taking over as Michigan State's starter.

When he returns, Cook and his teammates will have almost two more full weeks before they begin spring practice and put winter conditioning behind them. The late start -- only three Big Ten teams wait longer -- doesn't bother any of the Spartans.

Cook said playing until almost the end of April gives them a better chance to work outside and get better weather for the spring game. Others said the extra month gives them time to heal properly and take a break after a long fall season.

"It's a good time for us to get these workouts in," said linebacker Riley Bullough. "We're recovered from the season now, but it's nice to have a little bit of time to get away from football. After spring break we're definitely ready to put the pads on."

Bullough is the most likely candidate to take over the Mike linebacker position in the middle of the Spartans' defense this spring. He played inside and outside linebacker, along with a stint at running back, during his first two years on campus.

The junior also took advantage of the extra time off by watching film this winter. He said he's working his way through each game his brother Max, a former All-Big Ten linebacker for the Spartans, played to pick up tips on how to react faster.

The extra study time has given Bullough more of a sense of ownership at his position now that he's an upperclassman. He was one of the players leading linebackers through their drills Tuesday afternoon.

"I think the guys have seen me step up and be somebody they can look to out here and going into spring ball. I think that's important for a Mike," he said. "I think they expect me to be a leader, and I expect myself to be a leader."