"He feels good physically and the medical staff felt like he was in very good condition as far as getting on the field tomorrow," Farrell said before Friday's series opener at Dodger Stadium.
The 40-year-old, who's been monitored closely by the Red Sox during his final season, continues to deal with foot and ankle problems.
"The at-bats are the risk and reward inside that," Farrell said. "He was on the field last year and we have held off for obvious reasons, but with a right-hander going tomorrow, sandwiched by left-handers, we thought it was a good day to get him on the field."
Ortiz played first nine times during the 2015 season and took ground balls at first prior to Friday's game.
"He was real clear. He wants to play," Farrell said. "Any time we can get that bat in the lineup, especially against a right-handed pitcher, we are going to put him there."
Ortiz is having an impressive final season. He came into Friday's game batting .311 with 25 home runs and 87 RBIs. He leads the Majors in doubles (36) and the American League in slugging (.623) and OPS (1.021).
"This is one game. We totally understand the risk and reward here, but if it wasn't signed off by all parties, particularly David, we wouldn't even consider it," Farrell said. "You know what, games are taking on added importance. His bat in our lineup is an important one and it will be in the lineup tomorrow."
Quinn Roberts is a reporter for MLB.com and covered the Red Sox on Friday. This story was not subject to the approval of Major League Baseball or its clubs.