Johnson said he injured the muscle swinging the bat during batting practice and was tender. He said he's day to day.
"It was one swing," he said. "It tightened up a little bit, and I have a little knot in my left lat. They couldn't rub on it today because it's so sore, but tomorrow I'm coming in and we'll see how I feel."
Matt Downs, who was originally scheduled to start in right field, started at third base. Brian Bixler was inserted in right field. Johnson snapped an 0-for-12 streak by getting two hits on Saturday, going 2-for-3 with a run scored in a 3-2 loss to the Cubs. He's started 70 of the team's 79 games at third base and is hitting .280 with six homers and 34 RBIs.