ENGLEWOOD, Colo. (AP) -- Wes Welker won't play Thursday night against San Diego as he recovers from his second concussion in less than a month.
Broncos coach John Fox officially ruled him out Wednesday.
The NFL's protocol for concussed players would have allowed Welker only to participate in light practice Thursday and only if he had passed baseline cognitive tests earlier in the week. For competitive purposes, Fox had been coy about Welker's status during the week, other than to say the receiver's health was the team's top priority.
Fox also said defensive tackle Derek Wolfe (illness) would miss his third straight game when the Broncos (11-2) host the Chargers (6-7)
Welker was going low to catch a pass Sunday when Tennessee safety George Wilson legally hit him in the side of his neck, knocking him from the game.
Welker also sustained a concussion Nov. 17 against Kansas City but played the following week at New England, where he spent his previous six seasons.
Welker has 73 catches for 778 yards and a career-high 10 touchdowns.
Tight end Jacob Tamme figures to serve as an able substitute in the slot. He filled in admirably when Julius Thomas was sidelined by a knee injury for two weeks and last week he had four catches for 47 yards after Welker got hurt.
''His role has changed this year,'' said Peyton Manning, who also played with Tamme in Indianapolis. ''He caught 61 passes last year. Obviously, Julius has played well this year and Tamme hasn't had as much playing, but he's had a great attitude. And when his number has been called he's come in there and been outstanding.''
Wolfe hasn't practiced since suffering a seizure-like episode Nov. 29. He made a brief appearance at practice Wednesday on his way to work out with the team's training staff and looked much lighter than his listed weight of 285 pounds.
As Wolfe walked past his fellow defensive linemen on the way to the weight room, Terrance Knighton broke away from the group to hug him.
Wolfe's ailment is one of many that have hit Denver's 25th-ranked defense.
Safety Rahim Moore underwent emergency surgery last month to fix a blood flow problem in his lower left leg and defensive tackle Kevin Vickerson went on IR with a dislocated right hip. Perennial Pro Bowl cornerback Champ Bailey has missed 10 games with a foot injury and Fox acknowledged Wednesday that ''we may have rushed him a little bit'' in bringing him back Dec. 1 at Kansas City.
Bailey sat out the second half of that game and was deactivated last week.
Undersized middle linebacker Wesley Woodyard's play and his playing time have slipped in large part because of a shoulder stinger he sustained at Dallas in October and recently aggravated. Last week, he played just 10 of 50 defensive snaps while 12-year veteran Paris Lenon got the start against the Titans.
Fox and defensive coordinator Jack Del Rio said Lenon deserved more snaps for the way he works at practice as much as Woodyard needed some rest to heal up.
Lenon, who started all 16 games in six of the last seven seasons, has started three games for the Broncos but his coaches and teammates say he approaches every week as though he's the starter.
''Either I'm not smart enough to approach it any other way or I'm smart enough that I approach it that way, I'm not quite sure what it is,'' Lenon said. ''But I know this: I have a single purpose and I go in one direction.''
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