Ross was released by the Diamondbacks in early April, as the club chose to eat the $9.5 million remaining on his contract ($8.5 million for 2015 plus a $1 million buyout for 2016). The Athletics snapped him up, but Ross recorded only two hits (both singles) in 25 plate appearances.
Ross, 34, battled calf injuries over the past two seasons, which unsurprisingly has sapped him of his power. After hitting 22 home runs in 528 plate appearances in 2012, he combined to hit 10 in 570 PA between 2013-14.
Now a free agent, Ross will try to continue his major league career elsewhere.