Cowgill, 26, posted a .269/.336/.317 batting line with a home run and nine RBIs in 38 games for Oakland last season. He spent most of the season with Triple-A Sacramento, where he batted .254 with four homers, 37 RBIs and 33 runs scored in 61 games. Cowgill has a .255 average in 74 career Major League games.
The outfielder was selected by the D-backs in the fifth round of the 2008 First-Year Player Draft out of the University of Kentucky, and he made his Major League debut with Arizona in 2011, compiling a .239/.300/.304 batting line in 36 games. He drove in two runs in the National League Division Series against Milwaukee that year and was traded to Oakland in December 2011 as part of a five-player deal.
Marte played with Double-A Binghamton last season. The 21-year-old infielder batted .251 with nine homers, 58 RBIs and 61 runs scored in 129 games.
Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.