JUPITER, Fla. • Chris Carpenter believes he will pitch this season for the Cardinals but has no idea when a short-circuited right shoulder muscle will allow him to return.
Carpenter returned to Roger Dean Stadium on Monday morning after four days of neurological testing in St. Louis. While Carpenter said doctors could not pinpoint the source of nerve irritation that has caused him weakness in the shoulder, he did indicate he would enter a program to strengthen the region before again taking the mound.
"It's not working the way it should," Carpenter said. "I want it to work."
Carpenter carries a complicated neurological history. Nerve issues sidelined him in 2004 and 2008 and caused a lesser problem in 2010. He experiences permanent numbness in his right forearm as a result of his previous episodes but remains proficient enough to lead the National League in earned run average in 2009 and to amass 273 1/3 innings from the 2011 regular season and three rounds of playoffs.
Carpenter did not minimize his current condition but made clear he sees a way to pitch this season.
"When the nerves don't function properly, the muscles don't function properly," he said. "We're going to rest, let everything settle down, then go from there."
Carpenter experienced neck discomfort earlier in camp that was attributed to a bulging cervical disc. When he resumed throwing he felt pain and weakness behind his right shoulder.
"It just didn't respond. We were hoping it would respond the right way and it didn't," Carpenter said. "At that point I'm not going to hurt myself. We're going to make sure we get everything taken care of."
Team doctors suspected a nerve issue and Carpenter returned to St. Louis for what initially was believed to be two days of tests. When the source of Carpenter's problem proved elusive, he remained in town an additional two days, receiving a spinal tap last Friday, which necessitated that he remain home for two additional days.
The club has abstained from publicly setting a timetable; however, Carpenter probably will require at least three weeks to strengthen the shoulder before entering a throwing program that would carry him through at least mid-May.
Previously burned by overly optimistic predictions — some of them involving Carpenter — the club has described its co-ace's absence as indefinite. General manager John Mozeliak described the finding as "encouraging" but offered no projections.
"I don't know how long it will be before I throw again," said Carpenter, adding that his concern is not as high as it was before he was examined in St. Louis.
Doctors broached surgery as an option when Carpenter experienced problems in 2008 with a nerve bundle that ran from his neck area beneath his shoulder and into his right arm. At that time, Carpenter had pain and numbness in his pitching arm while the biceps fired inconsistently.
Carpenter ultimately rejected surgery in 2008, embraced rest and rehabilitation and finished as runner-up in balloting for the 2009 National League Cy Young Award.
"In '08, nothing worked," the 2005 NL Cy Young Award winner recalled. "Here, my arm is strong, my shoulder's strong. The only thing that's not strong is my rotator cuff. We need to make it strong."
Despite his optimism, Carpenter made clear he would not rush himself before regaining strength. Doctors told him four years ago that nerve issues could flare at any time. Hurrying to return only worsens symptoms.
Carpenter insisted he experienced no indication of a problem before arriving in camp last month. He said his placement on a modified throwing program that called for one or two fewer exhibition starts was coincidental.
The scope of last week's exams was broad. Carpenter had two MRI tests last Tuesday, nerve conduction tests Wednesday, an ultrasound and X-rays Thursday and finally received a spinal tap and CT scan Friday.
"I wouldn't recommend that to anyone," he quipped regarding the spinal tap.
Carpenter's strength program will pay particular attention to the right rotator cuff. He says his arm is fine to throw but that trying to compensate for weakness in the cuff area affects his command. Carpenter admitted being unable to throw with full force since facing teammates in live batting practice March 3.
The Cardinals have installed Lance Lynn as their fifth starter. Lynn has made three Grapefruit League starts and projects to work the Cardinals' fourth game of the season, on April 8.
Carpenter said he would return to St. Louis to continue his recovery when the team breaks camp next week.