5. David Wells (2005) - It's weird putting an ex-Yankee in this spot. And it's kind of cheating because Wells changed his number during the season from 3 to 16. But you cannot deny that Wells had a good season for the Sox in 2005. And we need someone for the fifth slot, so just go with it.
Signed as a free agent in the off-season, Wells posted a 15-7 record in 2005. His ERA was league-average (4.45, 102 ERA+) and his WHIP was a little high (1.31). But he helped stabilize a pitching roster where Tim Wakefield was the #1 pitcher and helped Boston into the post-season. His WAR was solid (3.2) and he was second in the AL in walks per nine innings (1.027). But that was his last good year; in 2006 off-season knee surgery diminished his ability and the Sox traded him to the Padres so he could fulfill his desire to finish his career on the West Coast.
3. Walt Dropo (1949-52) - The Moose!* A personal favorite from my alma mater (UConn) and arguably the best Serbian-American to ever play the sport**. Walt spent the first 3 1/2 seasons of his 13-year career with the Sox. While manning first base he not only went to the 1950 All-Star Game but won the AL Rookie of the Year. That season he hit a blistering .322 with a .961 OPS, 34 homers and 144 RBIs. Walt also led the AL in total bases and RBIs, and placed top 10 in six other categories. Those are impressive numbers even in the current era. He would also finish in the Top 30 for MVP voting twice; 6th in 1950 and 26th in 1952.
What held Dropo back from a bigger career was the wrist fracture he suffered in 1951. Unable to recapture the form he showed in 1950, he was traded to the Tigers in 1952 in the deal that sent Johnny Pesky to Detroit as well. Walt retired after the 1961 season and sadly passed away in 2010 at the age of 87. He is still recognized as one of the greatest athletes to come out of the University of Connecticut.
After he stopped playing following the 1964 season, he actually coached the Red Sox for the final stretch of the 1966 season. But then he was replaced by Dick Williams before the 1967 season began...and we all know what happened then. Runnels passed away in 1991 at the age of 63 following a stroke and was inducted into the Red Sox Hall of Fame in 2004.
1. Jimmie Foxx (1936-42) - The Beast. Double X. Six-time All Star wearing the '3'. AL MVP in 1938. Finished 2nd in the MVP voting in 1939 and 6th in 1940. Led the AL in batting average in 1938 at a .349 clip. Led the AL in OBP, Slugging and OPS in 1938 and 1939. Led the AL in total bases in 1938 with 398. Led the AL in RBIs in 1938 with 175 and was top 10 in that category every year from 1936-1941. Led the AL in home runs in 1939 with 35 and was top five in that category every year from 1936-1940. Foxx also hit a team-record 50 home runs in 1938, topped only by Hank Greenberg's 58 that year. The record would stand until 2006 when David Ortiz hit 54. Foxx's yearly average over this period was 32 HR, 115 RBI and an OPS of 1.007, amazing numbers in any era. His average WAR per season was 4.8 and he led the AL in WAR with a 7.6 in 1938. His defense was also solid; he was top 5 in fielding percentage at first base for three seasons (1937, 1939, 1941) and led the AL at first in 1937 with a .994 percentage.
Foxx was a monster on the field, but his ability diminished rapidly after 1940. Depending on whom you believe, it was due to either heavy drinking or a chronic sinus condition. Not many years after he retired. But he was (and remains) one of the greatest players of all-time for not only the Sox but for all of baseball. He rightfully made it into the Hall of Fame in 1951.
* He was called "Moose" because he grew up in Moosup, Connecticut.
** Fans of Pete Vuckovich would disagree with this assessment.