The Dodgers were working with a 13-man pitching staff until Sunday's move, leaving them with just a four-man bench. When Ramirez left Saturday's game against Colorado in the top of the fourth inning after bruising his thumb while being jammed from a Juan Nicasio pitch, that reduced the bench to three.
Though the Dodgers do not expect to put Ramirez on the disabled list, he had a previously scheduled off-day Sunday and they were uncertain of his availability off the bench.
"We're kind of at that point where we're a little nervous about the throwing side of it, and if something were to happen, we'd be short," Mattingly said. "We're already short [on the bench] and that would put us short another guy, fielder-wise. And if we go another one short fielder-wise, it puts us in real danger."
Plus, the club is confident everyone in the bullpen is "back on track with rest," Mattingly said, which allows the Dodgers to go back to a 12-man staff.
Triunfel, 24, was claimed from Seattle on waivers April 2. He was hitting .291 with four doubles and four RBIs at Albuquerque this season. After debuting for the Mariners on Sept. 2, 2012, he has played 17 games in the Majors at shortstop, six at second base and one at third.
The Dodgers felt that Ramirez's thumb was a little better Sunday and that they might be able to use him as a pinch-hitter if necessary. Pregame, he was being fitted with different pads to protect his sore thumb at the plate.
Scott Miller is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.