There is no question from anyone who has watched him over his eight-plus seasons with Boston that he has been an invaluable contributor to its recent success and there’s a possibility that we have not seen him pitch for the last time in a Red Sox uniform. So how does he compare to others greats who have pitched for this franchise?

In franchise history, there have been 133 lefties who have started at least one game for the Red Sox. We looked at Baseball-Reference.com‘s Play Index and narrowed the search to those pitchers who toed the rubber for at least 100 games with Boston as a starter.

Top Career ERA+

Top Career WAR

Top Career WHIP

Grove, who is the only pitcher to notch his 300th victory in a Red Sox uniform, pitched eight seasons between 1934 and 1941. His ERA+ of 134 and WAR of 44.7 leads the franchise in both categories for left-handed pitchers. He is also sixth all-time in WHIP. Leonard, who pitched six seasons between 1913 and 1918 and was part of three World Series championships, has the second-best ERA+ in franchise history (134), is fourth in WAR (27.2), and third in WHIP (1.136), putting him very close to Grove.

Also showing up on all three lists is Ruth who, while better known for changing the game of baseball with his bat, was part of the same three world championships as Leonard and has the third-best ERA+ in franchise history for southpaws. Collins, while perhaps not as well-known to casual Red Sox fans, is also on all three lists, playing for two world champions in 1912 and 1915 and currently sitting at number two in franchise history for WHIP (1.134).

Lester, upon close examination, certainly matches well in all three categories. His ERA+ of 120 places him fifth behind Ruth, his WAR of 31.0 places him second only to Grove, and his WHIP puts him fifth in that category. Also consider that, save for Collins and Tannehill, every other player listed here is a member of the Boston Red Sox Hall of Fame, and it’s probably a safe bet to say that he will someday be there, too.

Yawkey’s first order of business after purchasing the club was to renovate the rapidly aging Fenway Park. He spent another $1.5 million on a near-total reconstruction, employing thousands of laborers who had been affected by the Great Depression; his efforts had the park turned into a palace when the gates opened in April of 1934.

Trying to build contenders, Yawkey would pull out his wallet on several occasions to pay big money for talent, sometimes wisely but more often foolishly; he mistakenly believed that his inheritance would solve any problem and often threw unheard-of amounts of money at players who were either unproven or past their prime. He also strongly resisted integration in baseball; as a result, Boston became the last club to field a black player, twelve years after Jackie Robinson’s rookie season, and continued to be dogged by charges of unspoken racial policies even after Yawkey’s death in 1976. As a result of his short-sightedness, only three times during his tenure as owner did the Sox win a pennant.

Even still, he managed to bring Hall-of-Fame talent into the fold over the years in the form of Joe Cronin, Jimmie Foxx, Lefty Grove, Bobby Doerr, Ted Williams, and Carl Yastrzemski. Yawkey also did his part for the local community; over the years, he funneled much of his time and money into groups like the Jimmy Fund, which continues to raise money for sick children through its affiliation with the Red Sox.

A sportsman in the truest sense of the word and regarded highly by his peers, Yawkey was later the first person elected to the Baseball Hall of Fame who had never served as a player, a manager, or a general manager.

In baseball, a pitcher must face a minimum of three batters in each half inning to record the required three outs.  While it is not uncommon for a pitcher to retire the side on three strikeouts, it is extremely rare to do so on nine pitches, the minimum number required to perform the same task.  According to Wikipedia, 43 pitchers in MLB history have combined to accomplish this feat 46 times; it is commonly referred to as the immaculate inning.  Lefty Grove, Sandy Koufax, and Nolan Ryan, all Hall of Fame pitchers, are the only ones to done so twice (Grove, who pitched for the Sox between 1934 and 1941, did it twice within a span of a month with the Philadelphia Athletics in 1928).

Martinez, in seven years with Boston, was well-known for his high strikeout totals.  In addition to his 117 wins and an adjusted ERA+ of 190, he averaged 10.9 strikes per nine innings pitched, best in team history (his career average of 10.040 ranks him third in MLB history).  Three times, he led the American League in strikeouts and in total struck out 1683 batters, which ranks him third in team history behind Roger Clemens and Tim Wakefield.  He is also the only pitcher in team history to strike out 300 or more in one season, fanning 313 batters in 1999.  The results of his success with Boston were two American League Cy Young Awards and four All-Star game selections, once as the starting pitcher in 1999.

Martinez opened the game facing right fielder Ichiro Suzuki.  Suzuki, the reigning American League MVP and Rookie of the Year, looked at two called strikes before being dispatched with a third strike swinging.  Left fielder Mark McLemore dug in next; after missing strike one and fouling off strike two, he took a third strike for the second out.  Finally, designated hitter Ruben Sierra, like Suzuki before him, took two strikes and then swung and missed on strike three to set a mark unequaled in team history.