Hanley Ramirez took over the designated-hitter spot and hit cleanup Thursday.
"Just meeting with him after yesterday's game and kind of getting more of a sense of what he's dealing with while he's in the batter's box, plus what he's battling in addition to that," Farrell said regarding the reasoning behind the decision. "We felt like, when he's right, that's when he's the most dangerous. We're just trying to get him right."
Farrell said Ortiz, a nine-time All-Star, has been sick, but isn't dealing with any injuries. The decision was more about allowing Ortiz to get right mentally, and he is continuing to work in the cages and stay in a normal routine despite not being in the lineup.
"It's a combination of a few things," Farrell said. "There's some of [the mental aspect], there's some of what he's dealing with, battling a little bit, but I think more than anything [he can] hopefully just take a little bit of a step back and regroup."
There's not a clear timetable on how long Ortiz will be out, but Farrell said it "probably will be" more than one day.
"After the game yesterday we spoke about it, talked about what's upcoming the remainder of this road trip," Farrell said. "Obviously, that's not to say we don't get him back at some point when we're here in Texas, but there are chances hopefully to accomplish a few things, and that's to get him over what he's dealing with."
Cody Stavenhagen is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.