"I'm too old to start getting mad and yelling," Pineiro said before Friday's game against the Mariners. "I'm healthy and feel good. That is the decision they made, so I'll go with it.
"How I look at it, we are 1-0 with me in the bullpen."
Had such a decision happened at the beginning of his career, Pineiro said he may have been more upset. Ten years in the Majors have taught him otherwise.
Already looking at video of his previous starts with pitching coach Mike Butcher, Pineiro believes his issues boil down to where he's releasing the ball.
He'll try to work on that in the bullpen, realizing that it could take only one strong performance to get back into a groove.
"The No. 1 thing is getting prepared quicker, but maybe I'll stay fresher in that process," Pineiro said. "Maybe I'll feel strong for one inning and feel better. We'll find out."
In his last four starts, Pineiro went 0-3 with a 14.85 ERA. He also gave up a total of 22 earned runs and 29 hits in 13 1/3 innings.
"Our goal is to have him find it and get back out there," Angels manager Mike Scioscia said. "We have a lot of confidence in JP when he is on. We saw it early in the year, and it has been diluted as the season has gone on. It's his command, too, and he needs to get that back."