The Phillies did not provide a medical update on injured slugger Jim Thome on Monday afternoon, but it is clear that his recent back injury will prompt the team to handle the 41-year-old with caution.

Charlie Manuel and Ruben Amaro Jr. entered the season hoping that Thome could start one or two games per week while Ryan Howard recovered from surgery to repair a ruptured Achilles tendon. But Thome is just 2-for-18 with 10 strikeouts, three walks and no extra base hits this season. On Saturday night, he started at first base for the fourth time this season, but left in the fifth inning after feeling his back tighten up while sliding into second base.

When asked if Thome's back, which was a concern when the team signed him, makes it difficult to start him at first base, Manuel replied, "Yeah."

"You never know when it's going to tighten up on him," Manuel said. "He said it happened to him when he slid and hit the bag and come up. He can go quite a while sometimes and not have it flare up on him. But then it can happen. That's kind of what it is."

Thome was expected to take some light swings with the bat yesterday. He was examined by team doctor Michael Ciccotti on Sunday.

Manuel said it will be difficult for Thome to stay sharp for pinch-hitting duty if he is unable to get at-bats in the field.

"It's going to be hard for him," Manuel said. "You never know when he might walk up there and catch one, though. He puts a swing on the ball, he's usually going to move it. That's the upside to it.

"He takes a big stride and he takes a hard, quick cut. You've got to get your timing. There's got to be some kind of timing. The ideal pinch-hitter is usually a short guy with a short, quick swing. He's a singles hitter. That's the ideal. At the same time, in the National League, you need a guy with power, a big guy sitting on the bench who can  take one swing and tie or win a game for you. That can be very important too."