CHICAGO -- Chase Utley sounded encouraged Thursday evening at Wrigley Field, although that does not mean he will be back in the Phillies' lineup in the next couple of weeks.

He still has steps to take.

But he said he took a positive step on Wednesday, when he fielded ground balls during batting practice for the first time since rejoining the team on May 5. Utley, who is on the disabled list with chondromalacia in his left knee, said he still feels some discomfort in the knee, but it has improved.

"Over the past year or so, I know the pain threshold I can play at," he said. "And right now, I'm in the good zone. ... There's a little discomfort, but that's a part of the whole process. Last year, when I started taking ground balls, it was a little uncomfortable as well, but the more I did it, the better I became at it."

Utley offered no timetable for his return, but the plan remains the same -- continue to field ground balls, take batting practice until he feels he is ready to play in games. Once he feels he is ready, he will head to Clearwater, Fla, for a rehab assignment with the Class A Threshers.

Utley said earlier this month that he planned to pick up the pace with fielding practice, but that did not happen until Wednesday.

He explained the wait.

"I was doing some things inside," he said. "I'm trying to get to a point where when we start going for it, I feel pretty comfortable. I've realized over the course of this time that the more I push it and feel uncomfortable, the worse it can get. We try to make small progressions. Taking ground balls yesterday was a good sign. I felt pretty good today."

Utley took ground balls again Thursday. He said he might pull back on Friday.

"One thing is, you don't want to overdo it," he said. "Today, I'll take some ground balls. Tomorrow, maybe I'll slow it down a little and pick it up again. It's all going to depend on how I'm feeling. Right now, I'm feeling pretty good. ... It was good to wake up feeling pretty good. That's a good sign."

Asked if he thought he could progress quickly now that he is finally on the field, he said, "I wish I could tell you. Obviously, the better I feel, the shorter it will take. But it's still going to take a little time to get to game speed."

Polanco rests sore left knee

CHICAGO -- Phillies third baseman Placido Polanco joked Thursday he might need to strap on catcher Carlos Ruiz's shin guards before he steps into the batter's box.

He has fouled several balls off his left knee in recent days, including one Wednesday that forced him out of the game in the seventh inning. He said he felt a little better Thursday, but his knee remained sore.

Phillies manager Charlie Manuel did not start Polanco on Thursday. He had Ty Wigginton at third base instead.

Polanco thought he could pinch-hit Thursday, but was not sure about running or playing in the field.

Luna's slam translates into more playing time

CHICAGO -- Hector Luna on Wednesday became the first player to hit a grand slam in his first plate appearance for the Phillies since Gene Freese on April 18, 1959.

It was not a surprise to see Phillies manager Charlie Manuel start Luna at first base Thursday. He loves home runs.

"Because I wanted to," said Manuel when asked why he started Luna. "That's what made me do it. I looked at [Cubs starter Chris] Volstad and right-handed hitters hitting .300 on him, and we've had some success -- [Mike] Fontenot has had some hits against him -- but I wanted to get Luna in the lineup. I played him in Spring Training and stuff like that, and playing in a nice, comfortable yard, why not play someone who can hit it out?"