Padres' Waldron undergoes rear end surgery

San Diego Padres pitcher Matt Waldron underwent surgery for an infection in his rear end, adding to his injury woes. The 29-year-old knuckleballer struggled significantly last season, suffering an oblique issue in spring training and making only one start in June before finishing the season in Triple-A.

The surgery comes as a setback for Waldron, who was expected to be part of the Padres' rotation this season. The team has not yet provided a timeline for his return to action.