PHOENIX - Jonathan Papelbon walked to the bullpen in the sixth inning Sunday, as he does every time the Phillies play. The night before, he had thrown 29 pitches to record five outs because manager Charlie Manuel was desperate for a victory. That put his availability for the series finale in doubt.

Mike Adams waited for Papelbon to arrive before disclosing his own news. The setup man asked the closer if he could pitch.

"I'm good to go," Papelbon told him.

"Good," Adams said, "because I'm not."

Adams was sidelined by back spasms he said occurred within the last five minutes of batting practice before Sunday's 4-2 win over Arizona. He tried loosening up, and the training staff applied treatment to no avail.

His workload is under close scrutiny because of offseason surgery to correct thoracic outlet syndrome, which caused numbness in his pitching hand. (He had a rib removed.) Adams pitched three of four games, and the Phillies could not use him Saturday. He was an option Sunday until he told bullpen coach Rod Nichols that the back injury restricted him.

"It's the first time I ever had to bow out of a game," Adams said. "I've had little spasms before, but nothing to this extent."

Manuel said the team would "monitor" Adams. The pitcher did not believe the injury was serious.

When the Phillies tied the score in the ninth, Antonio Bastardo and Justin De Fratus combined to send it into extra innings. Papelbon converted his seventh save on 15 pitches.

Until Saturday, Papelbon had gone eight days without a save. He recorded the game's final five outs, and did so with a fastball that sat at 94 m.p.h. It was the seventh five-out save of his career and third with the Phillies.

"I asked him to do that," Manuel said. "I don't like doing that."

His fastball had added life Saturday. It averaged 94 m.p.h., according to PITCHf/x data. Diamondbacks hitters swung and missed at seven of his 24 fastballs.

Before that, Papelbon's fastball sat a tick below 93 m.p.h. in 2013. It hovered around 96 m.p.h. in his final seasons with Boston. Papelbon's arm action is traditionally slower in April. On Sunday, after the lengthy outing, his fastball averaged 93 m.p.h.

Nevertheless, he has a 1.15 ERA in 15 appearances, with 12 strikeouts and one walk. He delivered some of his finest work Saturday and Sunday.

Read Phil Sheridan' column about the 76ers.