Benson, ranked by MLB.com as Minnesota's No. 5 prospect heading into the season, had bone chips removed from his knee on Monday. But doctors found that there was a problem with the cartilage under his kneecap that required rest.
Antony, though, said Benson is expected to be ready for Spring Training.
"He'll do no strenuous activity for three to four months and then start his routine to prepare for Spring Training," Antony said. "The doctors said it should heal up fine."
Benson, 23, made his Major League debut as a September callup last season, hitting .239 with six doubles and a triple in 21 games. But he struggled in the Minors this year, batting a combined .202 in 76 games in Triple-A, Double-A and a rehab stint in Class A after undergoing surgery on his hamate bone in his left hand in late May.