That option could get Varitek up to $2 million more in incentives, as he'll get $400,000 each for 80, 90, 100 and 110 games started.
But with Martinez now entrenched as the starter, Varitek's playing time likely won't be as high. So, now the question is whether the veteran backstop -- now a 37-year-old backup -- will keep the heralded "C" he has sported on the top left of his Red Sox jersey for five seasons.
Epstein said he's just pleased Varitek chose to return.
"We're happy to have Jason back, and we look forward to a good year from him in 2010," Epstein said at the GM Meetings in Chicago. "He means an awful lot to the organization on and off the field. He helps solidify our catching position also and is a big asset to the pitching staff. We're happy he decided to come back and stay in the organization he's such an important part of."
Varitek, whose future home was in limbo until late in the offseason last year, played in 109 games in '09, batting .209 -- the lowest batting average of his 13-year career -- with 14 home runs and 51 RBIs.
Highly regarded for his ability to handle a pitching staff, Varitek led the American League with a 3.89 catcher's ERA and was tied for first with a .997 fielding percentage. But he also allowed 108 stolen bases, which led AL backstops.
When the club acquired Martinez from the Indians before the Trade Deadline, Varitek was limited to 28 starts at catcher from Aug. 1 until the end of the season and didn't play in the AL Division Series sweep to the Angels.
The Red Sox picked up Martinez's $7.1 million option on Monday, and Varitek had until midnight on Wednesday to decide on his option.
Varitek, a switch-hitter originally taken 14th overall by the Mariners in the 1994 First-Year Player Draft, is a career .259 hitter with 175 home runs -- all of which has come in a Red Sox uniform. He came to Boston along with Derek Lowe for Heathcliff Slocumb on July 31, 1997, and holds the Red Sox's record with 1,381 games as a catcher. Varitek also ranks among the franchise's all-time leaders in doubles (eighth), homers (12th), RBIs and walks (15th in each).
On Tuesday night, Epstein and Varitek's agent, Scott Boras -- who also represents the highly coveted Matt Holliday, among many others -- reportedly met for about 30 minutes in Chicago.