Hamilton was on the disabled list from Aug. 15 to Sept. 1 with pain and inflammation in his left knee. He was activated at the beginning of the month but was limited to pinch-hitting. Hamilton was 1-for-2 in that role, but the knee never responded to treatment and limited duty.
"It just isn't getting any better," Banister said.
The Rangers acquired Hamilton from the Angels on April 27, but he was still recovering from offseason shoulder surgery. He was activated on May 25, but he missed almost all of June with a strained left hamstring. In all, Hamilton played in just 40 games for Texas, hitting .257 with six home runs, 21 RBIs and a .431 slugging percentage.
"I don't have any questions about Josh's toughness," Banister said. "This guy worked hard and tried to be a full-go guy for us. I know he was in pain. When he came back to us initially, he had the hamstring issue, but he was also dealing with an oblique [muscle] issue. This is a tough guy that tried to gut out a lot of things. This one was a little much. He couldn't do as much, and it affected him swinging the bat."
The surgery will be performed by Dr. Keith Meister.
"The way it was described to me … it's a simple cleanup procedure," Banister said. "How Josh's body responds, we'll see. I don't know the timetable. I'm not ruling him out being available to us at some point. We'll know more after the procedure."
Hamilton is still under contract to the Rangers for two more years, although the Angels are picking up the bulk of his salary. The Rangers are still hoping that a full offseason will allow Hamilton to come to Spring Training next year at full strength.
"That's a goal for him and a goal for us," Banister said. "That would be a huge plus for us."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.