GREEN BAY, Wis. -- Jordy Nelson surprised Green Bay Packers coach Mike McCarthy with how much he was able to do in practice Thursday, but the team's No. 1 receiver still has hurdles to clear before he'll be allowed to play in the NFC Championship Game against the Atlanta Falcons on Sunday.

Nelson has broken ribs and an illness that kept him home Friday. McCarthy plans to give Nelson and fellow injured receivers Davante Adams (ankle) and Geronimo Allison (hamstring) as much time as possible before any decisions are made.

Adams and Allison also did not participate in Friday's practice. All three have been listed as questionable for Sunday's game on the team's official injury report.

"He practiced more yesterday than we anticipated," McCarthy said Friday, when asked about Nelson. "Making progress. Really, Davante the same way, and Geronimo. All three of the receivers will be given every chance to play in the game. So they have work to do, particularly in the area of rehab between now and the game."

As much as Nelson did in practice Thursday, he was not in pads like the rest of the team. That's an indication he was not medically cleared for contact.

Earlier in the week, Nelson was described as a long shot to play against the Falcons, according to a source. He broke his ribs less than two weeks ago, in the Packers' wild-card playoff win over the Giants on Jan. 8.

Nelson, who led the Packers in catches (97) and yards (1,257) and the entire NFL in touchdown receptions (14), called the injury "the worst pain I've ever felt" and said the decision to play will be based on pain tolerance, the ability to function and medical clearance.

"I've never played receiver with broken ribs," Nelson said Wednesday. "We'll find out, hopefully. ... If it happens, we'll see how it goes. But right now I'm just focused on getting back to full motion and doing everything and seeing if we can get that opportunity [to play], and it would be a great chance to have."

The status of Packers receivers Jordy Nelson (above), Davante Adams and Geronimo Allison have yet to be determined for the NFC Championship Game on Sunday. Otto Greule Jr/Getty Images

Adams, the Packers' No. 2 receiver, sprained his left ankle late in the fourth quarter of last week's divisional-round win over the Cowboys. He returned to the game, but he said that was based on adrenaline.

It's the same ankle he sprained last year, an injury that kept him out for three games and rendered him less effective upon his return. However, he said this week that if he plays, he won't be as limited as he was last season.

McCarthy said safety Morgan Burnett, who dropped out against the Cowboys with a quadriceps injury, is in the same situation as the three receivers and is also listed as questionable. Some or all of them may try to practice Saturday before the team leaves for Atlanta at 2 p.m. local time.

Center JC Tretter, who opened the season as the starter but hasn't played since a regular-season loss at Atlanta on Oct. 30 because of a knee injury, had a setback in his recovery and underwent surgery Tuesday, McCarthy said. That could leave the Packers with an available roster spot if they wanted to promote one of their practice squad receivers, Max McCaffrey or Antwan Goodley.