Ortiz was placed on the 15-day DL Wednesday with a strained right Achilles tendon. The designated hitter did not rupture or tear the tendon, a second MRI confirmed. The move is retroactive to Tuesday.
"It's probably going to be a week to 10 days before he's ready to go and take a little batting practice," said manager Bobby Valentine. "We'll give him a little extra time on the outside so he's ready to go when he comes off."
The Red Sox called up Mauro Gomez from Triple-A Pawtucket to fill Ortiz's spot on the active roster. Gomez, who can play first base and third, is in his third stint with Boston this season. On Wednesday, he started at DH against the White Sox. In his first eight games with the Red Sox, Gomez went 8-for-26 (.308) with three doubles and three RBIs.
"It seemed like he was the guy that was going to fill the bill and once David left, we really had no backup first baseman," Valentine said.
Ortiz sustained the injury while rounding second base on Adrian Gonzalez's homer in Monday night's 5-1 win over the White Sox. He said he felt "lots of pain" but didn't feel a pop.
The slugger leads the Red Sox with a .316 average, 23 homers, 58 RBIs and a .414 on-base percentage. Ortiz is the latest key player to spend time on the DL, a list that had included Dustin Pedroia, Jacoby Ellsbury, Carl Crawford, Josh Beckett, Clay Buchholz and Cody Ross.
"We're definitely going to miss him," said Crawford, who made his season debut only Monday. "It's a big disappointment for us. He's a bat that we'll definitely miss in the lineup. It's kind of unreal how many injuries we've had. I don't really know why it's happening. We have to pick up the slack."
Ortiz had at least one walk and one hit in his last 10 games, a franchise record.