Inside Lester's September struggles

With one game to go (for now), the Boston Red Sox will turn to their ace.

Jon Lester gets the start in Wednesday's season finale against the Baltimore Orioles, just the team he should want to face. No pitcher has been more dominant against a single foe.

Lester is 14-0 with 2.33 ERA in his career against the Orioles, the longest active winning streak for a pitcher against a team in the majors. The last Red Sox pitcher to reel off 14 straight wins against a team was Tom Brewer, who foiled the Kansas City Athletics back in the 1950s.

For Lester, who last pitched Saturday, it will be his second career start on three days' rest. The first came under far less dire circumstances.

These days, the Red Sox can't seem to diagnose what's wrong with their starting pitching and its 7.28 ERA in September. But in early 2008, the ailment was clear.

Several Red Sox pitchers -- including Josh Beckett and Daisuke Matsuzaka -- were stricken with the flu that April. That led to consecutive days in which Boston's starter was scratched just before game time. Lester wound up facing the Angels on three day's rest April 23. He lasted just five innings and 80 pitches, allowing four runs in a Red Sox loss.

The Red Sox will be looking for a far different result Wednesday. The last time a Red Sox pitcher won the second of two starts in five days or fewer was Game 7 of the 2004 ALCS. That's when Derek Lowe beat the New York Yankees on two days' rest to complete Boston's historic comeback.

A random April start three years ago provides little insight into how Lester might fare Wednesday, except that he's not accustomed to this role.

Far more relevant than his Lester's limited short rest history are his recent struggles. In his past three starts, he is 0-3 with a 10.54 ERA. It's just the second time in his career that he's lost three straight starts, and the 16 earned runs match the most he's allowed in a three-game span.

The biggest issues have come against right-handed hitters, who have feasted on Lester for a .409 batting average and 1.117 OPS during this stretch. That includes a .500 batting average with runners in scoring position.

Righties are hitting .524 against his fastball over his past three starts compared to just .244 over the first 27. The miss percentage against his fastball has nearly tripled from 4.8 percent to 13.5.

Lester's normally dominant cutter has also been an issue against righties, who are hitting it at a .385 clip over the past three games (.222 before). As the heat maps show, control has been a major factor with the cutter.

Turning those numbers around will be essential to success Wednesday, particularly with fatigue a potential factor.

Jeremy Lundblad is a senior researcher with ESPN Stats & Information. He provides statistical analysis for ESPNBoston.com.