Backup C Shawn Riggans is unlikely to return any time soon after feeling discomfort in his right shoulder while making a pickoff throw to first in a rehab game on Thursday, manager Joe Maddon said.
 
Riggans, out since April 10 with right shoulder tendinitis, is headed for a Monday exam by Dr. James Andrews.

"It's never good when you have to take a guy out like that,'' manager Joe Maddon said. "Even going down there I know he was feeling better but I wasn't totally convinced. I know how badly he wanted to get back here. We'll just have to find out medically where it is. I'm not overtly optimistic that he'll be back anytime soon right now.''

Riggans was aiming to rejoin the Rays on Sunday. Michel Hernandez will remain the primary backup to Dioner Navarro. "He's done a great job,'' Maddon said. "We feel very confident when he plays.''

Also INF Adam Kennedy was traded to Oakland for a player to be named later and cash. The player is a minor-league position player who will be identified within a week or so.

When the Rays signed Kennedy after he released by St. Louis on the eve of spring training, there was an understanding that if he didn't make their squad and went to Triple-A Durham that they wouldn't keep him from an opportunity to get back to the major leagues. Whith Oakland 2B Mark Ellis expected to be sidelined 4-6 weeks after sustaining a left calf strain, that opportunity arose.

"It's an extended opportunity for Adam and we weren't going to stand in the way,'' executive VP Andrew Friedman said. "We're not a group that's going to stand in the way of someone, especially someone that hadn't played in the minor leagues in 10 years. ... It made sense for him and we made the best of it.''

Kennedy was hitting .280 in 23 games at Durham with 3 homers and 9 RBIs, playing first, second and third. "Quite frankly hate to lose him,'' Maddon said. "Really thought at some point this year he would have been able to help us and that's why we brought him in in the first place. He did a fine job down in Durham and I wish him well. They had a need.''