ORLANDO -- A's general manager Billy Beane continued to revamp his roster this off-season, trading left-hander Brett Anderson to the Colorado Rockies in exchange for left-hander Drew Pomeranz and right-hander Chris Jensen on Tuesday.

Anderson, talented but often injured, had a 3.81 ERA in five seasons with the A's but made more than 19 starts just once. He had a 6.04 ERA in 16 appearances last season, 11 of them coming out of the bullpen. With the addition of left-hander Scott Kazmir, Anderson, 25, and his $8 million salary for 2014 became a luxury that the A's turned into younger, cheaper assets.

"With the amount of guys we have, we knew we could use that to get younger guys with less service time, and that was attractive," Beane said. "From the Rockies end, they're probably getting him at a great time. He's been through the Tommy John. He's always been motivated. He's a hard worker, and this is the time to get him, because the cost of acquisition a couple of years ago on Brett, well there really wasn't one. He was an untouchable.

"We've gone through the years and built up a rotation, and the hard thing initially was trying to find a way to live without him, and then we found a way, with such an abundance, dealing from a position of strength."

Pomeranz, 25, will add to that strength. The fifth pick in the 2010 draft has a 5.20 ERA in 34 big league appearances but Beane expects him to benefit from getting out of Coors Field.

"Let's face it, Colorado is a different environment, but going back to his college days -- I saw him at Ole Miss -- and he performed as you'd want, a top five pick right off the bat," Beane said. "Colorado is a very unique environment for pitchers. He's only 25, and a lot of people still think very highly of his abilities, and we felt it was a good time to acquire him. Guys like this aren't that easy to acquire -- this young with this kind of upside."

Pomeranz will continue to be a starter, although the A's don't currently have a vacancy in their rotation. Beane said that if needed, Pomeranz could be used as a left-handed reliever who is effective against both left-handers and right-handers.

Jensen, 23, has a 4.22 ERA at three minor league stops and will provide minor league depth.

Staff writer John Hickey contributed to this report.