"A type of tumor is basically what it is, within the sheath of the finger," Keith Dugger, the Rockies' head athletic trainer, said. "There's a hard substance underneath it.
"There are a couple of things it can be. The doctor is tending toward maybe what we call a neuroma, a scarring around a nerve, a big bundle, a wad of some sort. Also, there was a vascular component. So there was maybe the possibility he had a vessel that popped from the original swelling that he had. Maybe it calcified, or hardened. We really don't know until they do the biopsy."
Gonzalez experienced three bouts with sudden and unexplained swelling that forced him out of the lineup. On May 29, after the first two episodes, he met with hand specialist Dr. Thomas Graham and his staff in Cleveland, but MRIs and ultrasounds did not produce a definitive answer. There was believed to be a foreign body in the finger, but even that wasn't certain. After another flareup last week, the Rockies placed Gonzalez on the 15-day disabled list.
Not long after Graham performed the operation, Gonzalez tweeted:
Tuesday's surgery was termed exploratory, but once doctors were inside, they found the source of the problem and removed it, cutting diagonally from the webbing between the thumb and index finger and the webbing between the index and middle fingers.
If the mass is benign, Dugger said, "Typically, it's a couple of weeks for the tissue to heal, and then he can get back his strength and start swinging.
"It was a little bit more invasive, meaning they took out a larger piece than they thought or what the MRI revealed. But this way we feel we saved time going in there and getting what was in there causing the pain and discomfort that he had."
Dugger emphasized that although the issue can't be taken for granted, such issues are common.
Rockies broadcast analyst and former infielder Jeff Huson had a growth removed from the webbing between the ring and middle fingers of his left hand during his 12-season Major League career (1988-93, 1995-2000).
"It bothered me sometimes when I'd grip the bat because it pushed on the palm, in the webbing of the fingers," Huson said. "Then I got to the point where I tried to catch the ball and it hurt.
"I went to the doctor and said, 'There's something, and I can't get it to move or go away.' He tried to squeeze it and see if it would break up, and it never would. That hurt. Then they opened it up during the offseason. They took it out, did the biopsy and it was just a mass of stuff."
Gonzalez's mass has prevented him from doing his usual "mass of stuff," as he was hitting .255 with eight home runs and 31 RBIs in 52 games.