ENGLEWOOD, Colo. -- Once again, "probable'' wasn't a strong enough designation on the team's injury report for Denver Broncos interim coach Jack Del Rio.
Having cleared all of the tests in the league's concussion protocol, Welker participated fully in Friday's practice and is set to take his usual allotment of snaps against his former team in Foxborough, Mass.
"First and foremost, we've done the right thing by the player and he's safe to return,'' Del Rio said. "That's first and foremost.
"It's kind of like Peyton a while back: If you had a 'definitely will go' category, he'll probably be on there. ... He'll play.''
Welker, who left last Sunday's game in the fourth quarter with a concussion and neck injury, practiced on a limited basis Thursday. He was listed as probable on Friday's injury report.
He suffered a concussion after a 20-yard catch-and-run play in the Broncos' win over the Kansas City Chiefs. He left the game, returned for four plays and made one more catch, then was pulled for good.
Welker said Thursday he was "doing everything I possibly can,'' to play in Sunday's game and that he had been given good reports from doctors through the week.
The biggest question mark for the Broncos is tight end Julius Thomas, who suffered a right knee injury against the Chiefs and was limited in practice Thursday and Friday after being held out of Wednesday's workout. Thomas was listed as questionable and will likely need to show some improvement over the next two days to be in the lineup Sunday.
"He was limited again today,'' Del Rio said. "We don't play today, we still have a couple more days, but he was limited in what he could do.''
Thomas is fourth on the team in receptions with 45 but leads the club in touchdowns with 10.
Cornerback Champ Bailey (left foot) was limited all week and is listed as questionable, but he said he'd determine his status before Sunday's game. Bailey said he wants to test his foot on the FieldTurf playing surface at Gillette Stadium.
He suffered his original injury on Seattle's FieldTurf and aggravated it at Indianapolis' Lucas Oil Stadium, which also has FieldTurf.
"I don't want to say I'm going or say I'm not; it's all about getting on that turf,'' Bailey said. "It is frustrating. I'm a football player, and not being able to play, it bothers me. I'm just trying to be patient.''
Del Rio said it's a "strong likelihood" Bailey will return this season. He wouldn't commit to Bailey for Sunday.
All of the other players listed on the team's injury report, including Manning, took part fully in Friday's practice and will play Sunday.