The Red Sox have invited longtime catcher Jason Varitek to come to spring training as a non-roster invitee, telling him he would have only an outside chance of making the team, according to Jon Heymann of CBSSports.com.

Varitek is weighing accepting the offer or retiring, Heymann writes, citing people familiar with his situation. Heymann says Varitek, 39, does not appear to be considering playing anywhere other than Boston.

Heymann writes that the Red Sox "have made clear to him that if he did come to camp, he'd serve mostly as 'protection' in the event one of their two catchers, Jarrod Saltalamacchia or Kelly Shoppach, is hurt."

Varitek, who has played his entire 15-year career in Boston and was a key figure in the World Series title teams of 2004 and 2007, served as Saltalamacchia's backup last season, hitting .221 with 11 home runs and 36 RBIs in 68 games, but the Sox signed Shoppach as a free agent this offseason.

Heymann adds that the Sox were 42-22 in games started by Varitek, and 48-50 in games started by their other catchers, and that the staff ERA was 3.57 with Varitek, and 4.62 with Saltalamacchia.

But Shoppach led the American League by throwing out 41 percent of attempted base-stealers, while Varitek threw out just 14 percent. Saltalamacchia threw out about 31 percent. Shoppach also makes sense as a complement to Saltalamacchia in that he hits left-handed pitching well. Among active catchers, Shoppach's career .909 OPS against lefties is fourth-highest in the majors.

Ryan Lavarnway, who would be in the catcher's mix over the long haul, figures to start the season in Triple A.

The Red Sox have indicated they would be interested in Varitek having a role within the organization after his playing days are done. Last month principal owner John Henry said Varitek “should be a part of this organization for the rest of his life.”