As the Seattle Mariners have been in discussions with Felix Hernandez about a record-setting extension, concern has developed over the condition of his pitching elbow, a source says. The team and its franchise player had talked about a framework of a deal that would pay $175 million over the next seven seasons. But as of Sunday afternoon, sources say, the Mariners and Hernandez are not close to finishing an extension, because there are issues that the two sides are sorting through. The elbow issue is perceived by at least one of the parties in the deal as being a possible impediment to the completion of the new contract. "It's an issue," said one source. Hernandez has been a workhorse in his career, throwing 1620 1/3 innings already; in fact, since 1969, only three pitchers have thrown more innings before their 27th birthday, according to Elias Sports Bureau -- Bert Blyleven, Fernando Valenzuela and Dwight Gooden. But as salaries have skyrocketed over the last 15 years, teams have become increasingly wary of medical concerns.