BOURBONNAIS, Ill. -- The depth the Chicago Bears built in the secondary over the past two seasons is being put to the test in training camp.
Backup Zack Bowman's pulled hamstring and starter Charles Tillman's recovery from back surgery have the Bears down to Trumaine McBride at left cornerback. McBride normally is a right cornerback. Chicago also is moving Corey Graham to cornerback after he spent the offseason working to be a safety.
The Bears already are young at safety with Kevin Payne and Danieal Manning, which only compounds coverage problems in the secondary. Manning has now moved positions three times in his three-year NFL career.
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"We've got to be able to handle it now because it could happen in the regular season," Manning said Thursday. "You just don't know."
Coaches hope Tillman is back for the regular season. Graham is listed day-to-day, but hamstring pulls sometimes linger.
"I don't think it was a real bad pull or anything like that," coach Lovie Smith said. "He should be back in time."
This instability comes with Manning starting at free safety after starting only one game there last season when the team still had oft-injured veteran Mike Brown.
"Injuries are unfortunate, but we have Trumaine McBride there (at cornerback) who has stepped in and played a number of games in a starting role," veteran right cornerback Nathan Vasher said. "We feel we won't miss a beat. We have so many really good players it gives us that kind of depth in the secondary."
McBride actually tied for the team lead in pass breakups while starting nine games at right cornerback in 2007 as a replacement for Vasher, who suffered a groin injury. Now McBride is on the other side of the field.
"Obviously I know the defense better, so I think that's my biggest (reason for improvement) from my rookie year until now," said McBride, a seventh-round draft pick out of Mississippi in 2007. "I just feel more comfortable playing right corner. We have drills, and we work both sides in them, but I feel more comfortable playing the right side."
Career Statistics
Games/Starts: 46/30
Tackles: 179
Interceptions: 5
Manning went from free safety in Chicago's Super Bowl season of 2006 to nickel back last year, and he even started two games at cornerback in 2007. Now he's starting at free safety -- though he moves to nickel in passing situations and second-year pro Craig Steltz comes on to play free safety.
Manning received special tutoring from Smith last year when he moved to nickel back.
"I think I've accepted the challenge," Manning said. "I love nickel now a whole lot. It was an ideal situation for me when they told me I would be at free safety but go to the nickel. I tried to get into the grind and pick up as much experience at both as I could."
Graham is making the greatest adjustment by going back to cornerback and also learning to be a reserve nickel back. The third-year pro from New Hampshire prepared to challenge Steltz at free safety before training camp. Then Tillman's surgery set off a chain reaction.
"It was a bit of a shock to me after I'd just gotten moved six weeks (before) to safety and they were telling me that was going to be my position," Graham said. "But you just go with it, you just try to get back on your techniques and get better and better, and just roll with whatever happens and just try to get on the field."
The Bears also signed center Donovan Raiola on Thursday. Raiola has been with the St. Louis Rams, Seattle Seahawks, Pittsburgh Steelers and Arizona Cardinals, but he hasn't yet played in a regular-season game.
Copyright 2009 by The Associated Press