Phoenix, AZ (Sports Network) - The Arizona Diamondbacks designated outfielder Jason Kubel for assignment.
Kubel had been signed as a free agent by Arizona from Minnesota in December of 2011, but the 31-year-old has struggled to a .220 average, five homers, eight doubles and 32 RBI in 89 games this season.
Kubel was placed on the DL on April 13 with a strained left quadriceps, which he suffered on April 5 against the Brewers, and missed a little more than two weeks of action.
Arizona also selected the contract of pitcher David Holmberg from Double-A Mobile. The 22-year-old left-hander went 5-7 with a 2.66 earned run average in 25 starts for the Southern League club in 2013.
Holmberg will make his major league debut on Tuesday.