Allen broke a bone in his foot Sunday against the Seahawks and wasn't on the practice field Wednesday as the Panthers started getting ready for Arizona and the NFC Championship.
"He's trying to do everything he can to get ready," Rivera said.
"But I don't want him coming in thinking he's going to play no matter what. At the same time, I've got a group of guys I've got to get ready to play with or without him. I don't want to give any false indications either way because I want these guys focused in on preparing for themselves."
If Allen can't go, Kony Ealy will likely slide into the starting lineup with Mario Addison seeing an uptick in snaps.
--While starter Jonathan Stewart was resigned to watching Wednesday's practice, the Panthers saw another one of their running backs return.
Stewart, who missed the final three games of the regular season with a foot sprain, tweaked his ankle in the divisional round win over Seattle. But there's not much concern about his status just yet.
"It's just bringing him along," said coach Ron Rivera, who added Stewart did go through installation periods. "He played a hard game and we're just going to ease him back into action."
For Fozzy Whittaker, it was his first practice since he suffered a high ankle sprain in Week 17.
"It's definitely not 100 percent yet, but it's something I can definitely work through," Whittaker said. "And being able to practice today was a huge confidence booster."
For most of the season, the Panthers made just three running backs active on game days -- Stewart, Mike Tolbert and Whittaker. When Stewart was inactive the final three weeks, rookie Cameron Artis-Payne finally had a shot to show some flashes.
Whittaker's return could force coaches to make a tough decision -- deactivate him or Artis-Payne on Sunday. But according to Rivera: "There's no dilemma."
Because Stewart and Whittaker are both at least somewhat gimpy, it's likely the Panthers will keep all four backs active as injury insurance.
--Defensive tackle Dwan Edwards (foot) sat out practice Wednesday, but it was more of a vet day than an injury concern.