ARLINGTON -- The Rangers optioned pitcher Kazuo Fukumori to Triple-A Oklahoma on Friday while waiting to see how long third baseman Hank Blalock will be sidelined with a strained left hamstring muscle.

Blalock was not in the lineup on Saturday night and is not expected to play on Sunday. The Rangers are off on Monday and will wait until Tuesday before making a decision regarding whether Blalock should be placed on the disabled list.

"Hopefully, it will start to feel better, and in three or four games, I'll be back on the field," Blalock said before Saturday's game with the Twins. "If not, we'll cross that bridge when it comes. We don't want to make any decisions right now. I'll be honest with them on Tuesday."

Blalock injured the hamstring running the bases on his 10th-inning double in a 6-5 victory over the Twins on Friday night. He was replaced by pinch-runner German Duran, who scored the winning run on David Murphy's single.

"I ran around first base, and it just felt like somebody hit me or shot me from the stands," Blalock said. "It just balled up. I've never done this before. It's something new to me. I just wanted to make sure I could hobble into second base."

Ramon Vazquez started at third base on Saturday, and manager Ron Washington said he and Duran will platoon there until Blalock is ready. Travis Metcalf, who filled in at times last year when Blalock was out with a bad shoulder, is not an option. He had surgery in Spring Training to repair a torn hamstring muscle and is still working out in Surprise, Ariz. He has yet to play in a game.

Fukumori was sent down to make room for Sidney Ponson, who was called up on Saturday night to start against the Twins. Fukumori had been brought up just two days ago, but made just one appearance during his second tour of duty with the Rangers, allowing three runs in 2 1/3 innings against the Tigers on Thursday.

"He just got caught up in the numbers," Washington said. "He was the last one we added. That was the decision."