SURPRISE, Ariz. -- Relief pitcher Derrick Turnbow has agreed to stay in the Rangers organization and start the season at Triple-A Oklahoma.

Turnbow allowed three more runs in a 10-3 loss to the Giants on Tuesday and has an 8.10 ERA for the spring. He admitted he needs work on his mechanics and fastball command. Turnbow is in camp on a Minor League contract, and he could have opted for free agency if he wasn't added to the Major League roster. Being able to stay in touch with pitching coach Mike Maddux was a significant factor.

"I've been struggling with consistency all spring," Turnbow said. "I need more time to get the rust off and get my mechanics right."

Turnbow, who has been dealing with mechanical and shoulder problems the past few years that have affected his command, had a 15.63 ERA in eight appearances with the Brewers last year and a 10.50 ERA in Triple-A. He did not pitch after July 12, and an MRI revealed he had a partial tear in his rotator cuff.

Turnbow was an All-Star for the Brewers in 2006, but he finished that season with a 6.87 ERA. He had a 4.53 ERA in 77 appearances in '07. He was 7-1 with a 1.74 ERA and 39 saves for the Brewers in 2005, his best season in the Major Leagues.

The move opens up a spot for Jason Jennings in the bullpen.