Schilling also played a key role in Boston's 2007 World Series championship, adapting to diminished velocity and finding a way to beat the Indians in Game 6 of the ALCS and the Rockies in Game 2 of the World Series.
But 2008 was not kind to Schilling. After signing a one-year, $8 million deal to stay in Boston, the righty had immense pain in his right biceps area before Spring Training even started.
His bid at rehab went for naught, as Schilling had to undergo surgery in June and didn't throw a pitch the entire season.
Schilling has said several times since the surgery that he is leaning toward retirement. However, he has also hinted that there's a chance he would pitch the second half of the season for an interested team, much like Roger Clemens did the last two years of his career.
For his career, Schilling has a 216-146 record, a 3.46 ERA and 3,116 strikeouts. Perhaps even more impressive is what Schilling has done in the month of October, going 11-2 with a 2.23 ERA in 19 starts. Schilling was co-MVP of the 2001 World Series for the Arizona Diamondbacks along with Randy Johnson.
First baseman Sean Casey, who served in a reserve role for the Red Sox in 2008, also filed for free agency. Casey hit .322 with no homers and 17 RBIs in 199 at-bats.
The third Boston player to file for free agency on Friday was right-hander Bartolo Colon. The Red Sox signed Colon to a Minor League contract in Spring Training and he spent more of his season rehabbing from various injuries than he did on the mound.
Colon, the American League's Cy Young Award winner for the Angels in 2005, made seven starts for the Red Sox, going 4-2 with a 3.92 ERA.
When the Red Sox informed Colon in late September that he'd be used out of the bullpen for the rest of the season, he left the team and went home to the Dominican Republic. At that point, the Red Sox put him on the suspended list.
Catcher Jason Varitek, Boston's most significant free agent, filed on Thursday. First baseman/outfielder Mark Kotsay and pitcher Mike Timlin and Paul Byrd have yet to file, but are all but certain to do so in the next few days. There's a strong chance that Timlin, 42, will retire.