Hamilton had an MRI and was examined by Dr. John Preskitt. Rangers assistant general manager Thad Levine said what had been a groin strain had migrated to the abdomen.
"I don't think he felt comfortable at this juncture saying definitively no surgery or definitely he'll be back in two weeks," Levine said before the AL West-leading Rangers lost to the Yankees 12-3, opening a six-game trip to New York and Boston.
The injury is much like a sports hernia, and Levine said a second opinion is needed before it is determined whether surgery is needed.
"I think that still represents worst-case scenario, in which we are very hopeful it's not going to come fruition," Levine said. "They said in a week or two he could show significant improvement, so I think there's a chance that the DL stint will be exactly what he needs. That probably in this instance represents the better-case scenario."
Levine said rest and anti-inflammatory medication might alleviate the injury, sustained May 17 when Hamilton crashed into an outfield wall while making a leaping catch against the Los Angeles Angels.
Levine said it also was possible Hamilton would undergo the sports hernia surgery that Dr. Ulrike Muschaweck has performed on many athletes in Munich, Germany, a procedure Levine said may now be available in the United States. Many soccer players have returned to practice from that operation within two weeks.
"We want to learn a little more about that," Levine said.
Hamilton went on the DL retroactive to Monday, and outfielder Brandon Boggs was recalled from Oklahoma City of the Pacific Coast League prior to the start of a three-game series at the New York Yankees.
Hamilton is hitting .240 with six homers and 24 RBIs after a breakout season in 2008, when he batted .304 with 32 homers and 130 RBIs and thrilled fans during the All-Star Home Run Derby at old Yankee Stadium. He was sidelined from April 27 to May 12 with a strained left ribcage, an injury sustained when he crashed into a fence at Toronto while chasing a flyball.
Boggs hit .226 with eight homers and 41 RBIs in 283 at-bats for the Rangers as a rookie last year.
Right-hander Vicente Padilla, sidelined since May 16 with a strained right shoulder, was activated and started against the Yankees. He gave up seven runs, seven hits and four walks in 3 2/3 innings, his ERA rising to 5.57.
To clear a roster spot, the Rangers optioned right-hander Guillermo Moscoso to Oklahoma City