MADISON, Wis. The clock is ticking on Shelton Johnson's college football career at Wisconsin. As a senior who burned his redshirt year in 2008, only a handful of games remain for him, regardless of whether he plays.That's why Johnson, even if not fully healed from a broken right arm, has made his push so quickly to see the field again as the Badgers' starting strong safety.Johnson sustained the injury Sept. 8 during a Week 2 game against Oregon State. The initial diagnosis indicated Johnson would be sidelined for six weeks, but he has returned in less than four.Technically, Johnson has been medically cleared provided he wears a cast of some sort, although he admits playing this Saturday against Illinois could create issues."It's still broken, honestly," Johnson said following Wednesday's practice. "It's healing but it's not completely healed. It's only been about three and a half weeks. It's almost there. It's not whole. I'll say that. It's not like it was against Oregon State."Wisconsin coach Bret Bielema said Johnson wouldn't start against Illinois, "but he's there for us if we need him." Johnson said he would definitely be back the following week for a crucial Big Ten game against Purdue.If Johnson does play in some capacity on Saturday, he would provide tremendous leadership to Wisconsin's secondary. Johnson, one of six co-captains on the team this season, has recorded 11 tackles with one pass deflection in two games. He has played in 37 career games with 15 starts, including 12 last season when Wisconsin reached its second consecutive Rose Bowl. "He's a guy that has given all the calls really the last two years in the back end," Bielema said. "A guy that obviously we missed in a lot of different ways. He's a playmaker and a guy that has seen a lot of football."Wisconsin co-defensive coordinator Charlie Partridge cited Johnson's experience, which will be needed against an Illinois team that uses multiple personnel shifts and offensive formations."You've got a guy out there that has the confidence in making the adjustments that we need," Partridge said.Johnson wore a green non-contact jersey on Wednesday, so he still has not been thrown into live game action since sustaining the injury. He underwent surgery the next week and had pins inserted into the arm. "I knew something was wrong with it, but I didn't think it was broken until probably the next play," Johnson said. "I looked at it and saw my arm was crooked. That'll do it for you."Redshirt sophomore Michael Trotter has filled in for Johnson the past three and a half games. Trotter played in 12 games last season but didn't make any starts until three weeks ago against Utah State. While Trotter took Johnson's place, Johnson attempted to teach from the sideline and in the film room."It is hard," Johnson said. "But at the same time, sitting there and moping about it is not going to help my team win or it's not going to help the people that are replacing me do any better in the game for us to contribute to the team."This season, Trotter has recorded 20 tackles with one sack and one pass deflection but is still learning all the intricacies of the position. Trotter was beaten on a 3-yard touchdown pass against Nebraska last week and also missed an open-field tackle on quarterback Taylor Martinez's 38-yard touchdown run."Trotter is one of the smartest people on the team," Johnson said. "He knows everything he has to do, but he has to go out and do it. Tackling has been kind of an issue for him."More injury updates: Bielema said defensive ends Pat Muldoon and Brendan Kelly would play this week against Illinois. Muldoon sustained a broken thumb against Oregon State, and Kelly has been hampered with hamstring issues. Right guard Kyle Costigan, however, isn't likely to play this week. Costigan injured his right knee during the first quarter against Nebraska. He finished the game after being fitted with a knee brace, but he hasn't practiced this week."Costigan tried to go last night," Bielema said following Thursday's practice. "He didn't have a good reaction today, so I don't know if he'll be able to go in the game on Saturday."Redshirt junior Zac Matthias likely will start in place of Costigan. Matthias was the starter for the first three games but eventually lost his starting spot to Costigan.Running back carrousel: Bielema said he and running backs coach Thomas Hammock have come up with a plan to spread out carries among Montee Ball, James White and Melvin Gordon.Bielema indicated that even before the season, he hoped the touches for Ball would be around 25, with White touching the ball 15 times and Gordon 10."I don't want to just talk about it," Bielema said. "I want to see it out there on the field."Through five games, that plan has not materialized at all.Ball has carried 124 times (24.8 per game), White 31 times (6.2) and Gordon 12 (2.4). Ball also has seven pass receptions, White four and Gordon one."We haven't come close to hitting that yet," Bielema said, "but obviously it's something that's there."Follow Jesse Temple on Twitter.