Ortiz kept his back to reporters, sitting in front of his locker as he reluctantly fielded questions about why he wasn't starting against Orioles lefty Wei-Yin Chen.
"What do you want me to tell you?" Ortiz said. "You have to ask the manager. I am not the manager here. I'm just the player. I do what I get to be told. I'm not playing today, so I'm here in case he needs me later."
Ortiz, a left-handed hitter, has a .144 batting average against lefties this season. He is, however, hitting .308 lifetime against Chen.
"You look at the overall body of work against lefties, and that's what we are trying to address," manager John Farrell said.
Farrell said he informed Ortiz on Tuesday night of his decision.
"He understood it," the manager said. "David is a pro, and he understands there is some work to be done to get back to the normal levels against left-handed pitchers."
Ortiz, 39, played in 52 of Boston's first 59 games. His six home runs are fourth on the team, and he's tied for fifth with 21 RBIs. He has gone 66 at-bats since his last home run, May 19 against Texas.
Although Ortiz has struggled against lefties, he's got a .278 batting average against right-handers.
"Left-hander on the mound, and for the time being, we are trying to get David going against the lefties," Farrell said. "You look at what he's doing against righties and it's exactly the same of what he did a year ago when he was probably 20 percent of our overall offense."
Hanley Ramirez, who bruised his left knee Tuesday night, started at designated hitter for Ortiz. Farrell said Ramirez could have started in left field.