Glavine, 40, has experienced coldness in a finger on his pitching hand, and the New York Mets left-hander is scheduled to undergo medical tests next week in hopes of finding the cause, sources told the New York Daily News.
Glavine, a 287-game winner, is scheduled to have a CT scan Monday and an angiogram on Wednesday, the newspaper reported. Doctors are unsure whether Glavine's problem is related to a blood clot or possibly a "knot" in an artery near his left shoulder.
Agent Gregg Clifton confirmed Saturday that diagnostic tests are planned for next week, but he declined to elaborate. Mets spokesman Jay Horwitz would not acknowledge a medical issue.
Doctors apparently have ruled out an aneurysm, the newspaper reported. Last year, Mets reliever Felix Heredia experienced coldness and numbness in his pitching hand and ultimately was diagnosed with an aneurysm in the shoulder, which ended his Mets career.
Glavine (12-6, 3.92 ERA) hasn't been present in the clubhouse the last two days at Shea Stadium.
The loss of Glavine would be a serious blow to the Mets, who already have Pedro Martinez on the disabled list for the second time this season.