Fitzgerald, who did balance work and light jogging during the portion of practice open to the media, said his left knee is getting stronger every day.
"I'm highly likely," he said.
Then added: "But it's not my call though."
Later, Fitzgerald said "there's a likelihood I can play this week."
Fitzgerald said his knee didn't swell much but wouldn't go into more detail about the symptoms of the sprained MCL he suffered in Week 11 against Detroit. If he plays against the Atlanta Falcons, Fitzgerald said he'll wear a brace on his left knee.
"It's not restrictive too much at all besides it's just a little cumbersome," Fitzgerald said. "But it's protection and that's really what it's about. Just want to make sure you're out there and can do everything that you're capable of doing and if you do take a hit it's not going to be something catastrophic."
Even though he hasn't practiced this week -- and may not Friday, as well -- Fitzgerald feels prepared to play without taking a practice snap. He said Thursday that the only difference between what the healthy receivers do during the week and what he does is that they run routes in practice and he doesn't.
"From a mental standpoint, I'm honed in," Fitzgerald said.
Arizona saw a glimpse of how its offense plays without Fitzgerald in a 19-3 loss Sunday at Seattle, when it totaled just 140 net passing yards.
With a healthy Fitzgerald, however, defenses attack the Cardinals differently, offensive coordinator Harold Goodwin said.
"You worry about him because he's still Larry Fitzgerald -- a future Hall of Famer, a guy that's caught a lot of balls, caught a lot of touchdowns," Goodwin said. "It makes a difference having him out there.
"But for us it can't be a distraction if he's not."
Fitzgerald has taken pride in playing through injuries throughout his career but he also doesn't want to lose coach Bruce Arians' trust by leading him to believe Fitzgerald can be effective when injured.
Last week, Arians told Fitzgerald he needed a "speed guy" and someone he can rely on against the Seattle Seahawks. Fitzgerald, not wanting to mess with quarterback Drew Stanton's timing, knew he couldn't play at the level he's accustomed to and broke his streak of 110 consecutive games. Not playing Sunday was an "awkward" experience for Fitzgerald, he said, because it's been such a rare occurrence. He last missed a game in 2007 and didn't know what to do, where to stand, what -- or what not -- to say.
Then Fitzgerald had to also deal with the helpless feeling of not being able to help his team.
If a decision on Fitzgerald playing Sunday comes down to a simple question from Arians, Fitzgerald will err on the side of not letting his coach down.
"I don't ever want to mess up that trust," Fitzgerald said. "He trusts me and I don't ever want to break that. If I can go out there and I can go full speed, I'll tell him. If I'm iffy and I'm feeling I can't do it to the best of my ability, and I'm not as good as the guy that would come in and take my place, that's selfish.
"So, you have to make sure you're being aware of that."