PHOENIX -- Zack Greinke, the offseason acquisition the Milwaukee Brewers hoped would put them over the top in their pursuit of an NL Central title, is expected to begin the season on the 15-day disabled list after suffering a hairline fracture in one of his ribs playing pickup basketball.

The Brewers previously had said only that Greinke suffered an injury a couple of weeks ago during an off-the-field activity, but Greinke didn't receive the diagnosis of a broken rib until Tuesday, just after the team's Cactus League game with the Los Angeles Dodgers. At that point, Greinke told reporters he suffered the injury going for a rebound during a basketball game, before he pitched in any spring training games.

"Everyone always told me not to do it because I was going to get hurt," Greinke said. "It finally caught up to me."

Greinke, not knowing how severe the injury was, made two spring training starts after being hurt, allowing a total of one run on six hits over 3 1/3 innings. Now that the hairline fracture, which is between the seventh and eighth ribs on his left side, has been diagnosed, Greinke is expected to miss four to six weeks, which means he likely will begin the season on the 15-day disabled list.