What happened Wednesday was a much bigger step in his recovery.
"Running out there, running routes on air (by yourself), anybody can do that," Jennings said. "When you have a guy leaning on you and trying to jam you and reacting to it, you're kind of going to instinctively react, instead of strategically going about something. And that was huge for me to know that I can just react and respond to a guy up in my face and be able to still beat the jam and try to kick it into another gear when the ball's in the air."
Jennings tore his left medial collateral ligament in the Packers' Dec. 11 victory over Oakland, and sat out the final three games of the regular season.
"Right now, my knee is as stable as it's going to be, and it's been as stable as it's going to get for the last two weeks now," Jennings said. "So I've pretty much been cleared to do most things that we need to do as a receiver to perform at a high level. From a couple weeks ago, like I said, it was just all mental - just making sure that I trust my knee, to know that it's not going to tear again."
McCarthy did offer a few details on what he saw from Jennings.
Sitting out was tough for Jennings, who hadn't missed a game since McCarthy rested him and several other key players in the final game of the 2007 regular season.
"The first week I was out, the guys going down to Kansas City, having to watch that on my own television screen back home - that one was a tough one," Jennings said. "I thought that was tough, but then standing on the sideline against the last two opponents, Chicago and then Detroit, was even tougher. But it was fun seeing the guys having success and having fun and ultimately accomplishing the goal that we wanted, which was the No. 1 overall seed."
Even in the immediate aftermath of the injury, Jennings said he never feared he'd miss the rest of the season. He says he won't need any sort of surgery in the offseason.
"Once they kind of told me it was a torn MCL, I was disappointed," Jennings said. "But we've got some great trainers. Those guys in there worked day and night, 24 hours a day. We did some things in there that are putting me in position where I can compete in practice, have some time where I can go out there and kind of test it against some of the best DBs in the game. So we're OK with where we're at."
Jennings said he might have been able to return for the Detroit game if he was needed, but is glad he had extra time to heal.
"Honestly, I was telling the guys, it's really been a blessing in disguise," Jennings said. "Because late in the season, that's when the bumps and bruises kind of start to just nag and just stay, and you've kind of got to just fight through everything. For myself, I'm as fresh as I've ever been at the end of the season. So that's a plus. The only negative about it is the actual experience, you never want to miss games. But given this off week, being able to go out there and see defenses again, run routes and pick up the game speed all over again, it's going to be huge."