DENVER -- Rockies rookie right-handed pitcher Juan Nicasio is resting comfortably, in serious but stable condition, in the hospital after surgery to reattach fragments of the C-1 vertebrae in his neck.

Nicasio, 24, suffered the injury when hit in the head by a line drive off the bat of the Nationals' Ian Desmond during the second inning of the Rockies' 5-3 loss Friday night at Coors Field. Rockies head athletic trainer Keith Dugger said he is not sure if the neck fracture occurred when the ball hit him in the head, from the speed of his neck rotation after impact or when he landed face-first on the mound. Dugger also said he had not seen a C-1 vertebrae injury in baseball.

The surgery was performed overnight at Denver Health by Peter Witt, a neurosurgeon at The Spine Center at the University of Colorado Hospital, who inserted two screws into the vertebrae and a small plate in the back of Nicasio's head to stabilize the area. The plate will remain permanently. There was no damage to the spinal cord.

Nicasio is medicated but able to sit up and talk, which are good signs, according to Dugger. But when or whether Nicasio will return to pitching are unknowns, simply because the injury is so rare in baseball.

Nicasio also has a fracture along the side of his head. That fracture will not be repaired with surgery, but doctors are monitoring that injury with periodic CT scans for dangerous swelling and bleeding.

"The best-case scenario is he'll be there in Spring Training, starting for our club," said Dugger, who said Nicasio could be released from the hospital next week.

Dugger said he couldn't tell if Nicasio lost consciousness at any point. Nicasio was aware of what happened and was talking when Dugger made it to the mound to attend to him.

Dugger said general manager Dan O'Dowd, owner Dick Monfort, Rockies physician Jamie Genaurio and Rockies internist Allen Schreiber consulted with Witt and his team about the treatment options. Nicasio was aware of his options, which included being placed in a halo device or wearing a cervical collar, before opting for surgery.

"Him being a professional athlete and the potential to get back to pitching, his best option was to get this fracture back in its anatomical position, and pray, and hope and be positive," Dugger said.

Dugger said Rockies assistant clubhouse manager and equipment manager Joe Diaz, who speaks English and Spanish, and fellow pitcher Esmil Rogers helped keep Nicasio's parents informed in the Dominican Republic, since the rumor mill had his condition all over the place. Assistant athletic trainer Scott Gehret met with the players to keep them informed.

Nicasio, who was called up to the Rockies from Double-A Tulsa in May, was 4-4 with a 4.14 ERA this season and showed signs of becoming a key member of the Rockies' rotation in the future. Rockies manager Jim Tracy said the injury was difficult to watch.

Tracy was managing the Dodgers when Kazuhisa Ishii suffered a small skull fracture and a concussion when hit in the head by a line drive from the Astros' Brian Hunter on Sept. 8, 2002. Ishii returned the next season and pitched in the Majors through 2005.

"All I can tell you is my thoughts, the thoughts of this team and the organization, and my prayers are with this young man," Tracy said. "That is as devastating a situation as you can deal with in this game.

"When you look at where he was at the beginning of the year and where he's advanced to up to this point, I would say he was really, really emerging."

The Rockies called up right-handed pitcher Greg Reynolds from Triple-A Colorado Springs on Saturday to replace Nicasio on the 25-man roster. In addition, the club activated outfielder Carlos Gonzalez (strained right wrist ligaments) from the 15-day disabled list and placed outfieler Ryan Spilborghs on the DL with plantar fasciitis in his right foot.