ARLINGTON -- Rangers outfielder Nomar Mazara is headed to Triple-A Round Rock to begin a rehab assignment on Thursday against Omaha.
Mazara has been on the disabled list since the All-Star break with a sprained right thumb. He injured the thumb while trying to make a difficult catch in right field on July 14 against the Orioles.
Manager Jeff Banister said Mazara is expected to see time in the outfield and also serve as a designated hitter. The Rangers want Mazara to show that he is fully recovered before they make a decision on when he will be activated.
Mazara is hitting .272 with 15 home runs, 58 RBIs and a .450 slugging percentage in 91 games this season.
Tillman slated to make Triple-A start
Right-hander Chris Tillman, signed to a Minor League contract last Wednesday, will make his first start for Round Rock on Thursday. 
"It'll be nice to get him down there, get him pitching and see where he's at," Banister said. "Go pitch, show us where you're at right now, and let our scouts see that there's pitchability there."
Tillman, 30, spent the first 10 seasons of his Major League career with the Orioles before being granted his unconditional release on July 27. He has spent the past week working out with the Rangers.

The Rangers will likely want to see Tillman pitch for them as they continue to evaluate who will be part of their rotation next season. Tillman figures to be a candidate.
Over four seasons from 2013-16, Tillman posted a 56-30 record with a 3.91 ERA in 128 starts for the Orioles. He was selected to the American League All-Star team in '13.
"We know a lot about him," Banister said. "There's extensive history with Chris, and I like that [pitching coaches] Doug [Brocail] and Dan [Warthen] have gotten an extended period of time to see him, kind of work with him and start developing that relationship. That's necessary for him once he goes down and starts to pitch. If there's an opportunity, or something happens, you want him to come here, and they've already got that relationship."
Tillman was 1-5 with a 10.46 ERA in seven starts for the Orioles this season. His last big league start was on May 10 against the Royals.
Rangers beat
• Elvis Andrus extended his hitting streak to 19 games with a double in the first inning in Wednesday afternoon's 11-7 win over the Mariners. It is the longest streak in the Majors since Cleveland's Michael Brantley had a 19-game hitting streak in May.

• Shin-Soo Choo received a day off and was not in the starting lineup. Choo is hitless in his past 11 at-bats and is batting .141 (9-for-64) in his past 16 games.
• Delino DeShields is traveling to New York for the Rangers' four-game series against the Yankees. DeShields was placed on the seven-day concussion disabled list last Friday, but he said a specialist told him this week that he more likely suffered a migraine. DeShields said he did some running on the treadmill on Tuesday, and he could be ready to return as early as Sunday.