Left elbow tendinitis is the cause for Pennington's first career trip to the DL.
He is batting .197 with three home runs and 16 RBIs in 82 games for the A's this year. Pennington's .282 slugging percentage in the lowest in the majors, and his average and .259 on-base percentage are second lowest.
It's the third trip to the bigs this year for Sogard, who is hitting .145 with two home runs and six RBIs in 22 games.
Sogard, 26, is hitting .323 in 36 games with Triple-A Sacramento.