But the Phillies right-hander insists that this is just a stop-gap. One day, he wants to get back in the rotation.
"That's never changed," Park said. "That's the way that I can help the team now, so I just do my best. But my first goal and most favorite thing is to be a starter. I still believe I've got enough."
Park has earned the trust of manager Charlie Manuel, who originally viewed him as a middle reliever whose value came from being able to pitch two or three innings. Yet with J.C. Romero (strained left forearm), Chad Durbin (strained right latissimus) and Clay Condrey (strained left oblique) on the disabled list, Park has emerged as a critical and dependable late-inning arm. He is the go-to option for the seventh, setting up Ryan Madson and Brad Lidge for the final six outs.
"Why should I feel pressure?" Park said. "I just feel bad about guys that are hurt. I lost company, having fun together. I'm just hoping they come back as strong and healthy."
In 33 1/3 innings over seven starts in April and May -- before he lost the No. 5 job to J.A. Happ -- Park allowed 41 hits, 17 walks, five homers and 27 earned runs (7.29 ERA).
In 33 1/3 innings over his 22 relief appearances, Park has allowed 28 hits, nine walks, no homers and just 10 earned runs (2.70 ERA).
And in July, the 36-year-old South Korea native has allowed one earned run in 13 innings, posting a 0.69 ERA with three holds.
Manuel has repeatedly said that Park's stuff plays up better in relief, when the right-hander only has to face an opposing lineup once. Park disagreed.
"Why can you pitch the two, three innings," Park asked, "[and with the] same stuff ... not pitch six, seven innings?"
Park was an All-Star as a 28-year-old starter in 2001, capping off a five-year stretch with the Dodgers in which he went 75-49 with a 3.59 ERA. But he struggled mightily with three teams over the next seven seasons before returning to Los Angeles in '08, posting a 3.40 ERA as a reliever.
He appeared in back-to-back games just five times last season. He has yet to do so with the Phillies. But he feels much more comfortable out of the bullpen and is willing to pitch on consecutive days as needed.
Earlier in the year, Park needed extra notice to get loose because he was used to a starter's routine. That, too, is beginning to change.
"Sometimes it's physical, but sometimes it's mental," Park said. "My mental and physical [routine] got used to a starter, long warmup before you start in the game. ... Now I've got used to getting warmer quickly, and I learned from the other guys in the bullpen.
"Maybe I can get in more games more often."
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.