Ortiz, who has been the most productive hitter for the Red Sox all season, started at first base on Monday night. He will start at least one more game in this three-game series, and don't be surprised if he also plays two out of three at Wrigley Field over the weekend.
The left-handed slugger was batting .308 with 14 homers and 38 RBIs entering Monday.
"He's been an offensive force in this lineup in case we haven't noticed that," said Red Sox manager Bobby Valentine. "I'd rather not play many games without him."
Adrian Gonzalez started in right field while Kevin Youkilis got the nod at third. Will Middlebrooks was the odd man out.
"I think we've put to rest the ballpark concept with Adrian [in right]," Valentine said. "It's more about David and how much he will feel comfortable playing first base. Talking to David, he's good for two of these three to start with. We'll take it from there. And Adrian said he's fine with right field."