Cust, a left-handed hitting outfielder, was released by Seattle earlier this month after hitting .213 with three homers and 23 RBIs in 225 at-bats. He'll be assigned to Triple-A Lehigh Valley.
Cust averaged 28 homers and 76 RBIs between 2007-09 for Oakland. He had a career-best 33 homers in 2008. Cust also led the AL in strikeouts in each of those three seasons.
Cust is a career .242 hitter with 105 homers and 323 RBIs in 10 seasons with six teams.