Click photo to enlarge
Angel Villalona takes batting practice during the San Francisco Giants Minor League Mini Camp in Scottsdale, Ariz. on Monday February 25, 2008. (Nader Khouri/Contra Costa Times)

By Andrew Baggarly

MEDIANEWS STAFF

SCOTTSDALE, Ariz. -- Giants left-hander Noah Lowry will undergo surgery today to treat a rare muscle compression syndrome in his left forearm and is expected to miss at least the first month of the season, the club announced Thursday.

Lowry was diagnosed with exertional compartment syndrome, a condition more common in the lower leg muscles of runners. The club's medical staff believes that exercise-induced swelling within Lowry's forearm muscles compressed his arteries and nerves, causing him to feel tightness and fatigue.

Those symptoms forced a premature end to his season last August and prevented him from gripping the baseball as he walked nine of 12 batters in a Cactus League start Monday.

Dr. Gordon Brody will operate to snip open the fascia, which is tissue -- somewhat similar to a sausage casing -- that surrounds the muscle. Manager Bruce Bochy termed the procedure minor, though it is not arthroscopic and carries a small risk of nerve damage.

"It's not great news, but it's good news that we found out what's going on," Bochy said. "We wanted to identify the problem."

Lowry probably will be ready to resume throwing in two to three weeks, Bochy said. Lowry wouldn't be ready to pitch in a major league game until late April at the earliest, the manager added.

But any timetable amounts to informed speculation because of the unique nature of Lowry's injury. Exertional compartment syndrome is difficult to diagnose, and preliminary research by the Giants' medical staff has not found another major league player who has undergone a procedure to address it. The club's official news release did not include a time frame for recovery.

Lowry, 27, is expected to return to camp this weekend to begin his rehab program. The diagnosis was made after he underwent an EMG nerve conduction study, a forearm compartment pressure test and multiple MRI exams on his arm and hand.

Efforts to reach Lowry were unsuccessful.

Lowry led the staff with 14 victories last season, though he made his last start Aug. 29 because of weakness in his forearm. At the time, the Giants suspected the issue might have been related to an old bone spur in the back of his elbow. But it now appears to have been the early symptoms of the exertional compartment syndrome.

Lowry was scheduled to open this year as the Giants' No. 3 starter. Right-hander Kevin Correia, who was favored to win the final spot in the rotation, is virtually assured his place now. Jonathan Sanchez is the top candidate to replace Lowry, though he hasn't pitched well in two Cactus League games; left-hander Pat Misch will provide competition.

The Giants also could look outside the organization, where pitchers such as Kyle Lohse remain unsigned. David Wells, 44, was in the San Diego Padres clubhouse this week and told players that he still hopes to pitch. Bochy managed Wells in San Diego.

"We'll sit down and talk about our options," Bochy said.

Contact Andrew Baggarly at abaggarly@mercurynews.com.