Palmer, 35, had surgery to repair the torn anterior cruciate ligament in his left knee after getting hurt in a Week 10 game against the St. Louis Rams.
The team lost five of 10 games without him in the lineup and finished 11-5, good for second place in the NFC West. Arizona still made the postseason before losing to the Carolina Panthers 27-16 in the NFC wild card round.
Palmer only played in six games last season, as he also missed three games due to nerve damage in his right shoulder. He won all six of the games in which he appeared in 2014, completing 63 percent of his throws with 11 touchdowns and three interceptions.
Palmer says he was cleared to participate weeks ago, but was held out for precautionary reasons.
"I'm ready. I'm excited. I'm 100%. I'm cleared," Palmer said, according to ESPN. "I can do everything. I've tested out. Gotten stronger every week, every month, just ready to get going."
Palmer did not participate much during the team’s organized team activities, sitting out drills when the Cardinals defense blitzed. But he says he isn’t worried about getting hurt again.
"That's life," Palmer said, according to ESPN. "That's the job. I don't think much about it.
"That wasn't me saying I'm worried about somebody else. That was the trainers and the surgeon and the doctors and PTs and all that. I don't think twice about it."
Weeks before he was injured, Palmer signed a three-year contract extension worth $50 million. He restructured his deal this offseason, which saved $7.1 million in cap space in 2015 for Arizona.
"I feel great," he said. "I probably never worked this hard in my life and I've always worked hard. I feel as fast as I've ever been, as quick as I've ever been, I'm stronger than I've ever been just because I've been going since late November."
- Scooby Axson