PHOENIX -- Just two days after the Diamondbacks called up right-hander Billy Buckner, he was optioned back down to Triple-A Tucson to make room for another righty, Leo Rosales.

The D-backs bullpen has pitched a total of 24 1/3 innings the past five days, including three consecutive extra-innings games.

As was the case on Friday with Buckner, the move was made to give the 'pen a fresh arm.

"The bullpen is kind of hurting a little bit, so I'm just going in to help out a little bit," Rosales said. "I didn't expect [the call up] at all."

Buckner pitched twice for Arizona. In his first outing on Friday, he picked up the win against Kansas City after pitching a scoreless 10th inning. On Saturday, he threw 1 2/3 innings and allowed back-to-back homers.

Rosales saw action in 28 games in relief for the Sidewinders, going 2-1 with a 4.08 ERA in 35 1/3 innings. He went 9-for-9 in save opportunities. Rosales will be making his Major League debut with the D-backs.

Rosales said the club told him they may end up needing him for a while, or he might just be an innings-eater for the next few days.

The 27-year-old right-hander was acquired from the Padres last July in exchange for Scott Hairston in a rare trade within the division. While with the Padres, Rosales was described as having the best changeup in their farm system.