The 23-year-old took part in 12 plays Monday in his first action since undergoing microfracture surgery on his left knee in September.
Phillips slipped twice during the seven-on-seven drills at the University at Albany, but he quickly got up.
"It felt great," Phillips said.
Coach Tom Coughlin intends to spoon-feed playing time to Phillips.
Phillips won't be part of the Giants' evening practice Monday night, and he'll get roughly the same numbers of plays in Tuesday's single workout.
"If we can get through a couple of days here, we'll do some more with him," Coughlin said.
Phillips got off to a great start last season, making 16 tackles and intercepting two passes in the Giants' first two games.
But doctors found patella femoral arthritis in his left knee after the second game. Surgery ended his season and started a long rehabilitation.
"Honestly, I had no doubts," Phillips said. "No doubts at all because of the trainers and the doctors. They reassured me I could make a full recovery."
Teammates got Phillips to smile once he returned to the field, yelling, "Superman's back."
"He definitely plays like Superman," fellow safety Antrel Rolle said. "I am excited to see Superman get my backside once he gets back to playing shape. I know he is in playing mode. As far as the mental game, he is on top of it 120 percent."
The only problems were the two slips, which Phillips conveniently blamed on his cleats. He promised never to wear them again.
Phillips made an excellent read on an Eli Manning pass and dived in an attempt to defend it.
"I read his hips, saw who was missing out, and I went for it, came real close," Phillips said. "Maybe next time I'll get it."
If Phillips can return and play like last season, the Giants will have one of the deepest safety groups in the league with veterans Rolle, Deon Grant and Michael Johnson. Rolle and Grant were signed as free agents to bolster a unit that was among the worst in the league after Phillips was hurt.
"It was like a kid in a candy story," Rolle said of watching Phillips. "He's been missing a game he loved for the last year, so for him to be out there, it definitely lifted my spirits up a lot and I'm sure lifted his own spirits up a lot."
Safeties coach Dave Merritt said that having Phillips back was like getting a Christmas present. His only regret was that Phillips didn't get a chance to defend a long pass.
"That's where you're really going be able to tell if he's really able to get back there to make the play, and right now I truly believe that he's going to be able to do it from what I've seen in individual (drills)," Merritt said.
Merritt said Phillips made all the right reads on his plays, including a couple of extra plays during a four-minute drill.
"He wasn't supposed to go in four-minute," said Merritt, who had to bark at Phillips to get off the field. "I may get a tongue whipping by coach Coughlin."
Grant wasn't surprised that Phillips tried to sneak in the extra work.
"They gave him like two plays a period and he said, 'Give me three,"' Grant said. "If they had given him five he would've said, 'Give me six.' K.P. is still young now so let's not forget that because that means that he's going to be extra hungry."
Copyright 2010 by The Associated Press