A high ankle sprain suffered Tuesday apparently has ended Starlin Castro's season.

The shortstop suffered a left ankle injury while sliding into home plate in a four-run first inning in a 7-1 victory over the Milwaukee Brewers.

General manager Jed Hoyer said Castro is likely to be out four weeks but held out hope he could return before season's end.

"Right now the prognosis is probably four weeks to come back, but we're sort of operating under the assumption that he's out for the year," Hoyer said Wednesday before the series finale. "We're not going to shut him down. We're certainly going to work hard to come back and his mentality is that he can beat four weeks and come back."

Castro was batting .292 with 33 doubles, 14 home runs and 65 RBIs in 134 games in bounce-back season after hitting a career-low .245 in 2013.

First baseman Anthony Rizzo also remains out for the foreseeable future with a sore back.

The absence of Castro and Rizzo prevents a sneak peek this month at a potential future powerhouse lineup that would include prospects Jorge Soler and Javier Baez, now up with the Cubs.

"It's disappointing, but there will be a lot of time to see those guys together," Hoyer said.