It's been nearly 23 months since Brandon Beachy pitched in the majors. That will end Saturday.
A day earlier, Mattingly said it was unlikely the Dodgers would look to Beachy despite a lack of arms in the bullpen or the minors since the 28-year-old right-hander hasn't fully completed his rehab from the second Tommy John surgery of his career.
"Yesterday when we talked, I didn't really think he'd be the starter," Mattingly said. "We knew physically he was ready, just from the trainers and how's he been doing and bouncing back from everything. We just wanted to make sure he was ready to do it, and we didn't want to rush that."
Mattingly said Beachy approached him later and said he was ready to go, filling in for the spot left by the injured Carlos Frias. It will be Beachy's first start since Aug. 20, 2013.
Beachy said there were times in rehab when he was unsure whether he would ever make it back to the majors, but said his emotions would be in check Saturday.
"He's been through a lot. So my only reservation is that he's probably going to be a little jacked up and a little nervous," Mattingly said. "And you never know how it's going to go that very first game. But with that being said, we've been through a lot of guys, and we think he gives us the best chance to win."
Mattingly said Beachy will not be held to a strict pitch count, but did note that he has thrown as many as 90 pitches during his rehab and said that number will probably be close to his upper limit.
Beachy will be the 12th Dodger to start a game this season, more than any other NL West squad.
Mattingly also said left fielder Andre Ethier, who was out of the lineup Friday after leaving Thursday's game against the Phillies because of a quad injury, could have played if necessary.
Instead, Mattingly said, he decided to give the 33-year-old veteran a few days off as part of an ongoing effort to keep Ethier fresh for late in the season.