The true measure of his progress might be what happened afterward: Chamberlain fanned Philadelphia Phillies catcher Carlos Ruiz, his third strikeout of the inning.

Observers were buzzing about Chamberlain's performance — especially his 97 mph fastball — even after his mistake resulted in Feliz's blast. New York Yankees catcher Jorge Posada called his stuff "electric."

It was the kind of outing that's likely to rekindle the debate over whether Chamberlain is better suited for his role setting up closer Mariano Rivera, perhaps even succeeding him, or the starting job he had all season.

"It'll be another offseason full of questions," Chamberlain said before Monday's Game 5. "But like I said, (starting is) something I've wanted to do for a long time."

However, when pressed to clarify his preference, Chamberlain again resorted to his often-stated, "I just want to pitch."

The apparent vacillation is understandable, considering how overpowering Chamberlain often looks as a reliever. He broke in with 24 scintillating innings of relief in 2007, yielding just one earned run (0.38 ERA) and striking out 34.

Even Chamberlain, 24, acknowledges he can't pitch that way as a starter.

"You do the things you can do as a reliever because you've got to worry about guys the third and fourth time going through the lineup," Chamberlain said, "and how you got them out the first time is probably not going to work the second time."

Still, Chamberlain was a starter in college and in the minors, and the Yankees decided to stick with him in the rotation this season. The results were inconsistent and inconclusive.

Starting in all but his last appearance of the season, a one-inning stint to smooth his return to the bullpen for the playoffs, Chamberlain went 9-6 with a 4.75 ERA. He struck out 133 in 157⅓ innings — his most by far as a pro — but also walked 76. He allowed more than 1.5 base-runners per inning and hit an AL-high 12 batters.

"It was a year that he grew a lot as a pitcher and individual," manager Joe Girardi said. "And he's been effective during the postseason."

In nine appearances covering 5⅓ innings, Chamberlain has a 3.38 ERA, with eight hits allowed, six strikeouts and no walks. He also has one victory, oddly, from Sunday's Game 4, when the Yankees rallied for three runs in the top of the ninth.

Chamberlain saw the way he handled his setback as a sign of growth.

"I remembered what (Rivera) told me last year that carried over," Chamberlain said. " 'Just forget about it. You've got to make your next pitch.' "

Sounds like someone learning from the master.

Enlarge By H. Darr Beiser, USA TODAY Joba Chamberlain gave up a solo home run to Phillies third baseman Pedro Feliz, who tied Game 4 at 4-4 in the eighth inning, but still won.