Shortstop Mike Aviles, Kansas City's player of the year last season, will undergo Tommy John surgery and be sidlined for up to 12 months.

Manager Trey Hillman said Wednesday that Aviles will have ligament replacement surgery on his right elbow on July 8th, another blow to a team that has been hit hard by injuries.

After struggling through the minor leagues for seven years, Aviles was brought up from Triple-A Omaha last season and hit .325, tops among major league rookies.

He struggled this year and went on the disabled list May 23rd with what was described as right forearm strain.

A seventh-round draft selection in 2003, Aviles was Kansas City's feel-good story of the year last season. He joined the team when the Royals were on a 12-game losing streak, but sparked a turnaround, helping them to a 52-50 record the rest of the way. He was tied for fourth in rookie-of-the-year balloting after becoming the starting shortstop.

"It's very discouraging," Hillman said. "The guy's our player of the year after winning the shortstop job, battling his rear end off in the minor leagues to get here. It's impactful news, not only to us but to him as well."

Aviles is just the latest in a spate of injuries to plague the team. Center fielder Coco Crisp battled a shoulder injury and limited him to a career-low .228 average before he underwent season-ending surgery. Third baseman Alex Gordon played only seven games before going on the DL with a hip injury and probably won't be back until after the All-Star break.

In addition, catcher John Buck has missed almost a month with a back injury. The Royals went into Wednesday's game against Minnesota 10 games under .500 in the AL Central.

"The impactful guys in the middle of the field we put together for this roster this year, unfortunately, have been eliminated from the roster due to unforeseeable injuries," said Hillman.