The Broncos needed them back after losing Selvin Young (back) and P.J. Pope (hamstring) to season-ending injuries Sunday against Buffalo. They are the sixth and seventh tailbacks the Broncos have had to place on injured reserve this season.
Boyd, a seventh-round draft selection by Tampa Bay who was waived by the Buccaneers last summer, was promoted to the Broncos' active roster from their practice squad on Dec. 9, but was deactivated at Carolina and then cut and re-signed to the practice squad. He has yet to carry the ball in the NFL.
Haynes is a second-year player who was with the Broncos from Nov. 4-22 after entering the league as an undrafted free agent with Baltimore from Central Florida in 2005. He has three career rushes, three career receptions and three career special teams tackles while seeing time with the Ravens in 2005 and '08 and the Panthers from 2005-07.
Both are expected to back up Tatum Bell on Sunday when the Broncos play at San Diego with the AFC West title on the line.
The Broncos have also lost Ryan Torain (knee), Michael Pittman (spine), Anthony Alridge (leg), Peyton Hillis (hamstring) and Andre Hall (hand) for the season, leaving them with their eighth, ninth and 10th tailbacks.
"I would have said you're completely nuts if you thought we were going to go through seven or eight running backs," coach Mike Shanahan said this week.
He tried to look on the bright side, though.
"The good thing about it is we've had Cory Boyd, he's been with us. We've had him activated, he's used to our game plan. So it's not like we don't have something with Alex. He's been with us for a couple of weeks, so he knows the system," Shanahan said.
"So even though we had a couple of guys go on IR, we still feel that we've got guys that know our system and our terminology so we can still go out there and execute," Shanahan said. "So, that's a plus."