A's to call up former first-round Draft pick Green

KANSAS CITY -- Four years after being drafted by the A's as their first overall pick, infielder Grant Green is finally headed to the Majors.

According to a team source, Green, the team's No. 3 prospect, will join Oakland in Pittsburgh on Monday for the start of a three-game Interleague set with the Pirates.

The 25-year-old Green is hitting .318 with a .374 on-base percentage, next to 11 home runs, 25 doubles and 49 RBIs in 81 games with Triple-A Sacramento. His offense, though, has never been a concern for the A's so much as his defense, but having spent the majority of this season strictly at second base, Green is thought to have improved in that area.

It's at second base where Green is expected to make his debut, according to the official Twitter account of his high school, Anaheim's Canyon High: "Congratulations to Grant Green who just got called up and will start at 2nd base for Oakland tomorrow night!"

The corresponding move for Green is unknown, though the A's may potentially opt to designate Adam Rosales for assignment. Rosales has been a versatile piece for the A's since 2010, but he has struggled to consistently produce this season. He's hitting just .200, and he also committed a costly error in the eighth inning that led to Kansas City's game-winning run on Saturday.

Should Rosales be designated, the A's would have 10 days to trade, release or pass him through waivers to keep him in the system.