San Diego manager Bud Black said that "we hope he is back within a week, that's what we're hoping."
Kouzmanoff himself didn't have any different timetable, though he'll benefit from a day off Wednesday against the Giants and then Thursday's scheduled off-day.
"I've never had this before, but I think that calf is tough because it's [involved] in every movement," Kouzmanoff said. "We don't know how long. I guess the first 48 hours are important as to how it responds after that."
Kouzmanoff said the injury occurred in the eighth inning Tuesday when fielded a ball hit to him by Juan Uribe to start the inning.
"It was a ball to my left, and when I got it, I planted on my left foot to get in position to throw to first base," Kouzmanoff said. "That's when it happened."
Chase Headley moved from left field to third base for the ninth inning with catcher Nick Hundley taking over in left field. Headley got the start at third base Wednesday and likely will do so more often than not with Kouzmanoff out.
"As the game went on, it got progressively tighter," Black said.
Kouzmanoff pulled himself out of the game after the injury, when he decided he could be a liability on the bases or on defense.
"At first, I wanted to finish the game," he said. "But I felt if I were to get on base and in scoring position, I wouldn't be able to score."
Kouzmanoff is leading the Major Leagues in fielding percentage at his position (.990) and has committed three errors this season. Offensively, he hit his 17th home run of the season Wednesday and leads the team with a career-high 84 RBIs.
"It's tough; we've been playing some good ball," Kouzmanoff said. "Whenever you're injured, it's not fun."
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.