SAN FRANCISCO -- Giants first baseman LaMonte Wade Jr. will miss at least four weeks with a left hamstring strain, the team announced Tuesday.

Wade, who is batting .333 with two home runs this season, has been a regular at the top of the lineup. He aggravated the hamstring with a hard slide into second on a double Monday. It's the same injury that kept him out of the lineup over the weekend.

"He's as good a left-handed hitter that there is in the league right now," manager Bob Melvin said. "And not only that -- the flair for the dramatic, coming up big spots and getting big hits, as we've seen here for a while now. That's going to be tough to replace."

Wade was diagnosed with a Grade 2 strain. The Giants placed the 30-year-old on the 10-day injured list. Melvin said Wilmer Flores and Trenton Brooks are expected to fill in at first base. Brooks was called up from Triple-A Sacramento to make his major league debut Tuesday against the Philadelphia Phillies, batting ninth.

Brooks, who was batting .308 with four home runs and 18 RBIs this season in Triple-A, is a left-handed bat who the Giants hope can fill Wade's position against righties.

Flores is off to a slow start, hitting .214 with a home run through 45 games.