Pittsburgh, PA (SportsNetwork.com) - Pittsburgh Pirates second baseman Neil Walker underwent an appendectomy Monday night that landed him on the 15-day disabled list following the team's game against the Chicago Cubs.
The Pirates scratched Walker from the starting lineup prior to Monday's matchup because of abdominal pain that forced the emergency surgery.
Pittsburgh announced that it will call up its top prospect, outfielder Gregory Polanco, from Triple-A Indianapolis for Tuesday's clash with the Cubs.
Polanco, rated the No. 12 overall prospect in the majors by MLB.com, currently ranks second the International League with a .347 batting average and leads the circuit with 49 RBI and 134 total bases. The 22-year-old has seven home runs, 17 doubles, five triples and 15 stolen bases through 62 games with the Indians.
He'll be replacing one of the Pirates' most consistent hitters in Walker, whose 11 homers and 35 RBI are tied for the team lead. The switch-hitter is batting .280 in 62 games this season.