Ibanez -- named to his first career All-Star team on Sunday -- was hitting .312 with 22 homers and 59 RBIs before landing on the 15-day disabled list on June 18 with a strained left groin.
He does not know when he will rejoin the Phillies, or if he will be able to play for the National League squad in St. Louis on July 14.
"We're trying to get back as soon as we can and try not to think that far ahead," Ibanez said. "There is a rehab game [Monday], and that's as far ahead as I'm thinking right now."
The 37-year-old is expected to play only about five innings in the field. He does not think he will need many Minor League at-bats to regain his timing, but will follow the team's advice.
This is Ibanez's third scheduled rehab debut. He was originally supposed to report to Reading on Wednesday, which was pushed back to Thursday and then scrapped all together.
Though he has said for days that he is progressing, his groin is still not 100 percent pain free.
"It's good," he said. "It's good enough. You're going to go out there and you're going to see what happens."
Needless to say, though, Ibanez is itching to return. He played in all 162 games for the Mariners last year and in 2005, and in 159 games in '06, so this inactive stint seems like an eternity.
"If you're taking a few weeks off, that's worse than hard," he said. "I don't know what the word is. But yeah, frustrating is a good one."
David Gurian-Peck is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.