The Broncos (9-3) have scored just six touchdowns on 15 trips inside the opponents' 20-yard line since Thomas sprained his left ankle in the first quarter at St. Louis three weeks ago.
That 40 percent red zone efficiency pales in comparison to the 77 percent success rate (24 for 31) they had before Thomas got hurt.
''Julius is one of our top players and when you have one of your top players go out, you are going to miss him,'' Peyton Manning said Wednesday. ''We hope to get Julius back out there. There's no question when he's out there he makes a difference, he makes a lot of plays for us.''
Thomas leads the league with a dozen TD catches even though he hasn't scored since Nov. 9. He was limited at practice Wednesday and hopes to return to action this weekend against the Buffalo Bills (7-5).
Last week at Kansas City, the Broncos settled for five field goals from Connor Barth after stalling at Kansas City's 4, 6, 11, 14 and 19.
''I'm looking forward to getting back,'' Thomas said, ''so maybe my presence can have us kicking a little bit less field goals.''
Manning called it unfair to blame Denver's red zone woes solely on the absence of Thomas.
''I can't point it there,'' said Manning, who lamented his missed connections with Demaryius Thomas and Jacob Tamme last week when the Broncos scored on just one of six trips inside the 20 before a game-ending kneel-down at the 7.
''Every red zone opportunity has its own story,'' Manning said. ''Nobody wants to hear it. They just want to see if you got a touchdown or a field goal. Some way, we've got to find a way - I've got to find a way - to help us get into the end zone with Julius or without him.''
Thomas' return would add an intriguing challenge not only for the Bills but for the Broncos, who have had success emphasizing the run in Thomas' absence.
Behind an O-line that's jelling after a midseason shake-up, the insertion of third tackle Paul Cornick and the return of physical tight end Virgil Green, C.J. Anderson has run for 335 yards in back-to-back wins over Miami and Kansas City.
''C.J. has been awesome the past couple of weeks and it's been awesome to watch,'' Manning said.
If Thomas returns to the lineup, ''I don't really know how it's going to change them,'' Bills coach Doug Marrone said. ''Obviously, they've got another great player coming back. They can do so many things. They can hurt you so many ways. That's a challenge and you have to be careful. If you try to take someone out or you try to take someone away, they have so much talent on that offense that they'll exploit whatever weakness you have whether it's by putting too many guys in the box or putting too many in coverage.''
The Broncos want Thomas on the field but they don't want to take Green out - he was sorely missed in all three of Denver's losses. The game plan was built around him as a fullback and a second tight end at Seattle in Week 3, but he sustained a concussion on the first drive. His calf injury sidelined him at New England and St. Louis.
With Green back in the lineup, Denver has piled up 415 yards rushing the last two weeks.
Thomas said his return to action wouldn't necessarily mean the Broncos will go back to throwing the ball more. ''We're going to go with whatever's working well, and for us, we've been able to run that ball consistently well, and if that's the case, we'll continue to do that when I get back,'' he said.
Green said he can't venture a guess as to what happens upon Thomas' return, but he knows one thing: ''He's a red zone nightmare.''
Notes: WR Demaryius Thomas (foot) and C Will Montgomery (knee) were limited Wednesday. ... Bills QB Kyle Orton didn't want to reminisce about his time in Denver. Asked at the end of a five-minute conference call what comes to mind when he thinks about Denver, he replied, ''The mountains,'' then added ''See ya,'' and hung up.
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