San Diego Padres All-Star second baseman Mark Loretta will undergo surgery Tuesday to repair a tear in a ligament in his left thumb. Loretta injured the thumb sliding into first base on May 17 against the Braves. Loretta, who was selected to his first All-Star Game last season, appeared in the first 40 games for the Padres this season. He is hitting .300 with six stolen bases, five doubles, one triple and 13 RBI. In 2004, he established new career highs for batting average (.335), hits (208), doubles (47), home runs (16), RBI (76), runs scored (108), on-base percentage (.391) and slugging percentage (.495). He was originally signed by the Padres as a free agent on December 16, 2003 and has a career batting average of .303 with 60 home runs and 441 RBI in 1,165 games over parts of 11 Major League seasons with San Diego (2003-2005), Houston (2002) and Milwaukee (1995-2002).