LAKE FOREST, Ill. -- The Chicago Bears have placed Charles Tillman on injured reserve with the designation to return because of what team doctors initially diagnosed as a torn right triceps sustained in the second half of Sunday's 21-19 loss to the Detroit Lions.
The initial belief is that Tillman's injury will not require surgery, but the cornerback is being evaluated and is scheduled to receive a second opinion.
"It hurts," Tillman said. "I'm definitely sad. We have a lot of potential, and the fact that I'm no longer a part of that to help this team further succeed, that's the part that hurts.
"But my role is just to be the biggest cheerleader and supporter I can on the sideline."
Tillman is eligible to resume practicing in six weeks but cannot return to game action for eight weeks, meaning the Bears (5-4) will be without him for the rest of the season unless they qualify for the playoffs.
"I knew something happened in the second half," Tillman said. "I don't know exactly what play, I just remember shoving Calvin [Johnson] on one play and I felt something kind of strain, perhaps tear. I just felt a sharp pain.
"Yeah [they told me it was torn], but it's still being evaluated."
Despite the apparent torn triceps muscle, Tillman managed to finish the game, recording five tackles and two pass break-ups. He was beaten by Johnson for what turned out to be a game-winning 14 yard touchdown pass with 2:22 remaining.
Tillman refused to say that the triceps injury affected his performance.
"I don't think so," he said. "I think Calvin is a good receiver and he had a good game."
An 11-year veteran and two-time Pro Bowl selection, Tillman (150 career starts) ranks third in franchise history with 36 interceptions. He is the Bears' career leader in interception return yards (675), interception return touchdowns (eight) and defensive return touchdowns (nine).
Tillman leads the NFL with 42 forced fumbles since 2003. He is the only player since 2003 to record 40 forced fumbles and 30 interceptions. He missed one game this season because of a sore knee, an ailment he battled much of the season.
"It's just one of those seasons, man," Tillman said. "It's the National Football League. I think it happens to every team at least once a year. It just so happened the injury bug, it's got a hold of our team for some reason. I don't know."
Tillman, 32, is in the final year of his contract and scheduled to be an unrestricted free agent in the offseason for the first time in his professional career.
"To be honest with you, y'all are the ones who brought that up," Tillman said. "I was talking to [a Bears' media relations official] outside and he brought it up just beforehand. I didn't really think about it.
"I'm still under contract currently, so my whole view and thought process is I'm still a Bear. When I'm no longer a Bear, then we can talk about that. For right now, I'm still an employee of this organization. So no need to talk about it."
Six-year veteran cornerback Zack Bowman is expected to replace Tillman in the starting lineup for the remainder of the regular season.
Bowman has been used primarily on special teams the last three years, but he does have ample experience, appearing in 65 games with 17 starts and eight career interceptions. Bowman led the Bears with six picks in 2009.
"He's a veteran," Tillman said. "He's been in this defense awhile. He's been a starter on this defense before Tim [Jennings] got here. So I think Zack Bowman is a good fit. He's the next man up, and I have nothing but confidence and faith in Zack. I think he can get the job done."
ESPN.com Bears reporter Michael C. Wright contributed to this report.