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Peyton Manning has lost another of his top targets for the season.

Colts receiver Austin Collie suffered a concussion Sunday against Jacksonville, and the team placed him on injured reserve Wednesday.

Though Collie is in his second year, Manning feels like he's losing a veteran. Despite missing five games and more than a half in three others, Collie leads all Indy receivers with eight touchdown catches, is second in receptions (58) and third in yards (649).

"He's fast, he's got a good feel for zones, he understands defenses," Manning said. "He has his physical talents, but also, his experience has helped him play at such a high level at such a young point in his career."

Collie was injured late in the first half against Jacksonville when linebacker Daryl Smith appeared to hit him in the head with his forearm as Collie went low to make a catch. It was his second concussion of the season.

"He certainly is a guy that's going to be missed," Colts coach Jim Caldwell said. "From a medical standpoint, we are concerned more so about his health than anything else. This is the right thing for him at this particular time."

Manning had already lost tight end Dallas Clark and receiver Anthony Gonzalez for the season, and running back Joseph Addai has missed the past eight games with a shoulder injury. But the Colts (8-6) are fighting for a playoff spot, and don't have time to feel sorry for themselves heading into Sunday's game at Oakland (7-7).

"It doesn't do you any good to think about who's not playing and who's not going to be available," Manning said. "You have to go with who's available, and feel like with who's available, you can go out there and still make things happen."

Collie began to emerge as a go-to player when he caught seven passes for 123 yards and a touchdown in last year's AFC Championship Game against the New York Jets. He caught 11 passes for 163 yards and a touchdown in the season opener this season against Houston, and two weeks later, he caught 12 passes for 171 yards and two scores against Denver.

Collie's first concussion was the result of a scary collision in the second quarter Nov. 7 at Philadelphia. He did not play against Cincinnati the next week, then returned against New England the following week before leaving that game because he felt uncomfortable. He sat out against San Diego, Dallas and Tennessee before trying again on Sunday. He caught eight passes for 87 yards against the Jaguars before the hit by Smith.

"Obviously, it's disappointing for him," Manning said. "I know how hard he's worked all offseason. I know how excited he was to be back the other day, and how well he was playing."

Blair White will step into Collie's role. The rookie has 30 catches for 284 yards and three touchdowns this season. Caldwell said White's experience this season should make the adjustment easier.

"I do think that there are times when we talk about how, if we embrace a situation that occurs where we do have someone absent and we are able to develop some depth that somewhere down the line, that maybe, that's going to help you," he said.

Collie is the 17th Colts player placed on injured reserve this season, yet Indy is two wins away from another AFC South title.

"In our business, they don't give out any points for that," he said. "What counts and what matters is your won-lost record. That's really what you've got to focus in on is trying to win games. Anything else, I think, is kind of a side light."