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8/13/2014 2:09 P.M. ET

Guzman to head to rehab assignment Thursday

HOUSTON -- Astros first baseman Jesus Guzman will join Triple-A Oklahoma City on Thursday for a rehab assignment.

Guzman has been on the 15-day disabled list with back spasms since they flared up and forced him out of a game on Aug. 1.

"I feel really well, excited to go to California and get working again," he said. "I'm trying to be ready as soon as possible."

Guzman is expected to be at Triple-A for approximately four games before being reactivated. He likely won't test his back in the field right away.

"Yeah, the trainer Nate [Lucero] told me I'll DH for a couple of days and then maybe by the third day I'll play the field."

Guzman was mostly a platoon and utility option for the Astros before the injury. He started the majority of his appearances at first base, but also spent time in left field, as a designated hitter and even made an appearance at third base.

In his fifth Major League season, Guzman hit two homers and collected eight RBIs while batting .200 this season in 145 at-bats.

Marisnick shifts to right field with Fowler's return

HOUSTON -- Jake Marisnick doesn't particularly care where you play him.

Given his hitting of late, he just wants to be in the lineup.

With Dexter Fowler's return from the disabled list, Marisnick slid over to right field after playing center for Houston since coming over from the Marlins in the Jarred Cosart trade.

"Anywhere out there, just get me on the field and I'll be pretty excited just being able to play," Marisnick said. "Whatever I'm asked to do, you just want to play."

There was little chance Marisnick would be left out of the lineup, considering he's collected 11 hits in his past five games, including a 4-for-4 night and his first homer as an Astro earlier in the series against the Twins.

The former third-round pick has also produced multi-hit games in five of his first 11 appearances with the Astros, while anchoring an outfield that was missing all three of its starters in Fowler, Alex Presley and George Springer.

Marisnick can certainly play all three outfield positions, but it might be a stretch to say he's used to playing right.

He played center field for 427 of his 450 Minor League games and has never played anywhere else in 65 Major League contests. He played 10 games in right over the course of five seasons in the Minors.

"I don't think there'll be anything different, he's a guy who's played all three," manager Bo Porter said. "Again, you're looking at improving your defense because you now have three guys that are playing in the outfield who are capable of playing center field."

Marisnick said he's shagged plenty of balls in right during warmups recently and the adjustments are relatively small.

"The way the ball comes off the bat looks a little different, and the positioning changes," he said. "Nothing I can't handle. It's mostly minor things here and there."

Fowler batted in the cleanup spot in the lineup Wednesday as he returned from an intercostal strain that held him out since late June. Before the six-week DL stint, Fowler hit .303 with three homers, six doubles and eight RBI in June.

Chris Abshire is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.