SEATTLE -- The Rangers are concerned Joey Gallo may have fractured the hamate bone in his right hand, an injury that would require surgery and likely cost him all of August.

After an X-ray Tuesday night and an MRI on Wednesday were inconclusive, the Rangers sent Gallo back to Texas to see hand specialist Dr. Thomas DiLiberti to get a better feel. A tendon/ligament issue in the wrist area is also a possibility. Either way, Gallo is likely to end up on the injured list for the second time since June 1. The Rangers are expected to recall outfielder Willie Calhoun from Triple-A Nashville to replace him.

The small hamate bone serves no useful purpose in modern man. It can get irritated or fractured and cause discomfort. The solution is easy: A minor procedure to simply extract the bone. But the healing of the incision area takes the most time. Last year, Delino DeShields suffered a hamate bone fracture early in the year and never really recovered.

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"It's not good since we don't know what exactly is wrong," manager Chris Woodward said. "He was pretty sore [after Tuesday's game]. He puts a lot of torque on that wrist when he swings."

Gallo left Tuesday's game in the eighth inning. He had a bunt single in four at-bats before being replaced by Delino DeShields. Woodward said Gallo had been bothered by some hand soreness over the past week or so as he sunk into a slump. He was just 4 for 34 since the All-Star break.

With an outfield logjam, the Rangers had sent Calhoun to Nashville on July 16, a move that left Calhoun speechless. Since the demotion, he was 3 for 11 with four walks. The Rangers will likely have Calhoun split time in left field with Shin-Soo Choo.

Gallo also missed three weeks in June with a strained oblique muscle. He was leading the AL in OPS at the time of the initial injury.