"We don't have a ton of right-handed bats in the organization," Rockies general manager Dan O'Dowd explained. "We like his athleticism and love him as a kid."
However, the 27-year-old Murton struggled last season, hitting just .186 with eight RBIs in 70 at-bats, including .100 in 30 at-bats with the A's. He finished the season with Triple-A Sacramento, hitting .277 with one homer and 13 RBIs in 130 at-bats.
"It's a fresh start for him," O'Dowd said.
Wimberly, a 25-year-old infielder, hit .291 with 26 RBIs at Double-A Tulsa last year. He stole 59 bases, best in the Texas League and seventh overall in the minors.
Colorado selected Wimberly in the sixth round of the 2005 amateur draft. He has 181 stolen bases in 354 minor league games.
But with infielder Eric Young Jr. around, Wimberly was expendable.
"You have to trade someone of value to get somebody back," O'Dowd said. "We decided that E.Y. Jr. was ahead of him a little bit. Corey's a good player. He's going to help them, and turn out to be a good deal for them."
It's the second trade the Rockies and Athletics have orchestrated this offseason. In November, Colorado sent All-Star slugger Matt Holliday to Oakland for reliever Huston Street, lefty Greg Smith and promising outfielder Carlos Gonzalez.
Any coincidence the two sides got together for another deal?
"Not really," O'Dowd said. "We identified a group of right-handed bats in the game. [Murton] happened to be with Oakland."
The deal comes a day after Colorado agreed to a one-year, $7.05 million contract with third baseman Garrett Atkins, allowing the two sides to avoid arbitration.
Now, the Rockies can focus on baseball, not business.
"As I've said, contract signings are about the individual. Getting that behind us and focusing on the team is a priority for us," O'Dowd said.
The offseason has been busy for the Rockies. The team acquired durable right-hander Jason Marquis from the Chicago Cubs for reliever Luis Vizcaino in January, and signed relief pitcher Alan Embree to a one-year deal.
"We've all collectively put a lot of work in this winter," O'Dowd said. "Now we look at players up close and personal [at spring training]."
The Rockies' pitchers and catchers report for spring training Feb. 15.