Brewers center fielder Bill Hall will be out indefinitely after he badly sprained his right ankle.
He was leaping to try to catch Ryan Doumit's solo home run for Pittsburgh in the second inning today.
The injury to one of its top players could be a major setback to division-leading Milwaukee.
They have lost five of seven and were beaten in three of four in Pittsburgh.
Hall has a high ankle sprain, the more severe form of the injury and one that can sideline a football player for a month.
The Brewers aren't estimating how long their 2006 team MVP will be out, but it will be until after the All-Star break.
Hall returned to Milwaukee to see his own doctors and did not accompany the Brewers to their weekend series in Washington.
No fractures were revealed in X-rays taken in Pittsburgh, but Hall will undergo additional tests, including an MRI exam, in Milwaukee.