Wide receiver Randall Cobb has done a pretty good job of concealing the pain he has been feeling in his right biceps but there was no more hiding it Tuesday.

The Green Bay Packers receiver was grimacing after taking part in a team drill late in practice showing for the first time the difficulty he is having with an injury Cobb believes he suffered in the intrasquad scrimmage Aug. 3.

He is walking the fine line between playing through the pain and sitting out. Cobb can function more or less normally and doesn't seem to be hindered reaching out for a pass but with each practice he pays the price with shooting pain in his arm.

"I'm dealing with that" Cobb said. "The hardest part for me is that I'm a tough guy. I don't like missing practice. I'm trying to be smart and tough and that's a little bit difficult for me. I understand I have some limitations and have to be smart about it but it's difficult."

Coach Mike McCarthy said that he expected Cobb to feel discomfort for a while because of the nature of the injury. He said a lot goes into deciding whether it's best for the player to rest or to fight through the pain and often it is a joint decision between the training staff and the player.

In this case Cobb said he probably could do a better job of communicating with the coaching staff on what he's going through but he said he thought this was something every player goes through during a normal season.

"I know at some point during the season I'm going to be in pain and I'm going to have to play and I'm going to have to be productive when I do play" Cobb said. "So trying to push through right now is more of a mind-set for me. It's nothing to be worried about. I may look like I'm in a lot of pain and I may be in a lot of pain but I'll be fine."

The biggest reason Cobb said he is practicing is that he is not satisfied with his performance in camp. He wouldn't go as far as to say that a rash of drops the first week was the reason.

The Packers are counting on Cobb being a major part of their offense and maybe their return game too. Cobb will be the full-time slot receiver replacing the departed Greg Jennings and he's likely to see more attention from opposing defenses with Jennings gone.

Cobb did not play in the Arizona game and has a few days until a decision must be made about the game Saturday at St. Louis.

Game time: Coaches are going through the offensive installations with quarterback Vince Young the way they did with the rest of the team prior to his arrival but the emphasis for Young is different.

All this week Young signed Aug. 5 is working on mastering a limited portion of the offense so he can perform comfortably against the Rams.

"You have measurables and you have things that you look at in every player and pertaining to his position but when a guy has the unique ability to go win games I think you need to definitely make sure your system can take advantage of that." McCarthy said. "That's really what we're doing with Vince.

"I'm just trying to get him ready to go play. I want to see him play quarterback be comfortable playing quarterback so we can get a true evaluation on him."

Young gets a limited number of snaps in practice in the Packers offense and then takes the rest of his running the scout team. Aaron Rodgers and Graham Harrell get most of the reps within McCarthy's offense but some plays are saved for Young.

"When I look at Vince Young's particular situation I don't think it's realistic to ask a quarterback to come in at this particular time and get caught up to the other guys" McCarthy said. "The other guys have been here all throughout the spring and Graham's going on his third year and B.J. (Coleman)'s going on his second year so really the goal for Vince is to get him ready to play."

Support staff: After speaking at a news conference announcing his retirement as a Packer Ryan Longwell went down to practice and watched the ongoing battle between kickers Mason Crosby and Giorgio Tavecchio.

Longwell the Packers' all-time leader in field goals and field-goal percentage has known Crosby through the kickers fraternity and the fact their teams played against each other twice a season while Longwell was with Minnesota. They have talked kicking philosophy in the past and Longwell supported Crosby through his struggles last year.