KANSAS CITY -- The Cardinals' medical team diagnosed left-hander John Gast with a left lat strain Monday, a day after the club placed him on the 15-day disabled list.
"The timetable is to be determined, but the good news is that it's not the shoulder or the elbow," general manager John Mozeliak said. "Hopefully, it's something that won't take too long. With a lat, it can be up to a month or a month and a half. We'll see."
Gast was 2-0 with 5.11 ERA over three starts before the injury, throwing 12 1/3 innings.
Mozeliak was also encouraged that right-hander Jake Westbrook threw Monday with no ill effects. Westbrook has been battling right elbow discomfort.
"Clearly, the news of him throwing [Monday] was far more encouraging than it was three or four days ago," Mozeliak said. "I think there's a lot of positive there. He feels good about where he's going. Directionally speaking, seeing him maybe out on a rehab [assignment] in a week or two would be great."
Robert Falkoff is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.