Brewers first baseman Corey Hart, who's been struggling to try to return after offseason knee surgery, is likely to miss the rest of the year, sources said. Hart had extensive surgery on his right knee in January, and the Milwaukee Journal-Sentinel recently reported that Hart was experiencing left knee discomfort now, as well. Hart was scheduled soon to visit with noted Los Angeles surgeon Neal ElAttrache. The Brewers are waiting for more information before saying anything more definitive about his status than they've said, which is that he could be out until after the All-Star break. Brewers GM Doug Melvin, asked about the likelihood of Hart missing the rest of the year, suggested he isn't in position to say yet. "We don' know yet,'' Melvin said. "That's the problem. You really don't known until someone goes out on a rehab assignment. Until a guy plays games in rehab, you don't know. Guys can look they can play, but until they play with game intensity it's always hard to gauge.'' Melvin said there is no timetable being discussed at this point for rehab games for Hart. The loss of Hart has been a killer for the Brewers, as their first basemen have combined to post the lowest batting average (.186), on-base percentage (.230) and OPS (.542) in baseball. Hart, 31, hit 30 nhome runs with 83 RBI and an .841 OPS last year, when he also had knee surgery. The Brewers acknowledged a couple weeks that Hart might be out until after the All-Star break after originally hoping he could make it back sometime in June. Hart, who's been a notoriously quick healer in his career, in fact suggested in spring he'd like to retrun to play in May if he could. Hart, who was transferred to first base after playing right field most of his career, shocked teammates when he managed to make it back for Opening Day last season after offseasoon knee surgery, against all odds.