"I feel comfortable with Kendrick," Manuel said. "We've got the pitching to offset that. I've got a feeling [Lee] won't be out very long. When his time's up, he's going to be back."
Taking Lee's spot in the rotation, Kendrick will get the chance to prove his manager right on Monday when the Phillies open a three-game series against the D-backs at Chase Field.
Posting a 1.93 ERA out of Philadelphia's bullpen in four games this season, Kendrick started 15 games for the Phillies last season, going 8-6 with a 3.22 ERA.
Also dealing with injuries to their starting rotation after starter Daniel Hudson went on the disabled list on Saturday with a right shoulder injury, the D-backs will turn to reliever Wade Miley for Monday's start.
In 8 2/3 innings this season, Miley has allowed three earned runs on seven hits. However, giving Miley the start means the Arizona bullpen will be thinned out for the next few games.
"If I start Miley, what does that do to my bullpen?" Gibson said before Sunday's game against the Braves. "If he pitches good, he's out for five days. That changes the complexion of your bullpen."
Phillies: Lee, team taking cautious approach
While Lee said on Sunday that he and the Phillies discussed whether he could just miss a start or go on the disabled list with his strained left oblique, both decided it would be best to err on the side of caution.
"I feel like it should go away," Lee said. "But I've never dealt with anything like this before. It's something different. Hope we'll miss [only] a couple starts, and it's back to normal."
The Phillies placed Lee on the disabled list on Saturday, retroactive to April 19. He'll be eligible to return on May 4, when the Phillies play the Nationals.
D-backs: Bloomquist, Roberts sit
In an effort to help D-backs shortstop Willie Bloomquist and third baseman Ryan Roberts come out of recent struggles at the plate, Gibson gave both the day off on Sunday against the Braves. John McDonald and Cody Ransom started in place of the pair.
"They're pushing very hard, guys care a lot," Gibson said. "Probably a little too much, and they're getting too frustrated with the results. We'll give them the day off, maybe [Monday] and maybe the next day. But they might play [on Monday], too."
Bloomquist and Roberts are a combined 2-for-26 since Wednesday.
The D-backs have scored in the first inning in 11 of their 16 games this season (18 runs total).
The Phillies finished a Major League-best 30-14 in games against left-handed starting pitchers last season and are 2-2 so far this year.