"Phillies pitching coach Rich Dubee said he has a plan for his rotation this weekend in San Francisco, but he's not ready to reveal it.

Roy Oswalt, who pitched six solid innings in a rehab start Monday for Triple-A Lehigh Valley, is expected to be activated and start against the Giants. His normal day to pitch would be Saturday -- but that would be Cole Hamels' day to pitch, too.

So, who will get the extra rest?

"Probably, if you really want to look at it, more so Cole because of his workload," Dubee said. "But (Oswalt) has had an accelerated workload to get back here."

While Cliff Lee and Roy Halladay have enjoyed an extra day off between starts 10 times each this season, Hamels has only gone on long rest seven times, and he currently ranks third in the National League in innings pitched with 158. He's on pace to throw 240 innings this year, which would be 13 more than his previous career high.

Oswalt could throw a bullpen session this afternoon, and that might help make the final decision.

The right-hander, who hasn't pitched since June 23 due to a bulging disc in his back, threw six innings and allowed two runs while striking out four for Lehigh Valley on Monday and said that he hasn't experienced any back pain since returning to the mound last week.

In Monday's outing, Oswalt hit 92 mph on his fastball -- up about 2 mph from his first rehab start -- and showed increased command of his off-speed repertoire, throwing 90 pitches total.

"I'm probably not going to throw a no-hitter the first night out," Oswalt said. "But I feel pretty good. It's just a matter of executing pitches.""