Cliff Pennington's (elbow) rehab assignment could be a lengthy one. The A's not only want to make sure Pennington is healthy, but they'd like for him to get in a groove at the plate before being activated. He's off to a good start at Triple-A Sacramento, picking up three hits in his first seven at-bats. In the meantime, the A's will continue to go with a combination of Adam Rosales, Eric Sogard and Brandon Hicks at shortstop.