Royals catcher Jason Kendall will undergo right shoulder surgery on Friday and is out for the season, manager Ned Yost announced on Wednesday.

“He had an MRI on his shoulder on Monday and it showed extensive tearing in his rotator cuff,” Yost said. “It will be somewhere between eight to 10 months before he’s back.”

Although Yost said he hoped to have Kendall back “by the spring,” even just eight months would carry through the first month of the 2011 season in April. Kendall will be in the second year of his Royals contract.

Yost said Kendall was injured in mid-July sliding into a base against Oakland.

The catching for the last 30 games will be handled by backup Brayan Pena and Lucas May, just called up from Triple-A Omaha.

Kendall, who’d been an iron man behind the plate for most of this season, played in 118 games and batted .256.

–Dick Kaegel