Varitek will announce his retirement on Thursday in Fort Myers, according to The Boston Globe. The 39-year-old is reportedly expected to stay with the organization in some capacity.
Varitek, the Red Sox captain since 2005, joined the organization via a trade in 1997, and he's since become one of the organization's most respected players.
The three-time All-Star catcher finishes his career with a .256 average, 193 home runs and 757 RBIs. But perhaps his most valuable assets — leadership and grit — are immeasurable.
A two-time World Series champion, Varitek has also called a record four no-hitters, and has caught more games for the Red Sox than any other catcher in team history.
Only Carl Yastrzemski (23 seasons), Ted Williams (19) and Jim Rice (16) had longer tenures with the Red Sox without playing for another team.