Numbers tell tale of sickening month

The Boston Red Sox took another step toward collapse with Wednesday's 6-4 loss to the Baltimore Orioles.

The Red Sox dropped to 5-16 this month, a .238 win percentage that would be their lowest in September since going 4-18 (.182) in 1926. It would be their lowest win percentage in any month since a 3-10 April in 1966 (.231).

Boston hasn't won back-to-back games since August. According to the Elias Sports Bureau, that stretch of 23 games is Boston's longest since a 28-game run in 1994.

With their final seven games coming on the road, the Red Sox hope to avoid the worst September collapse in major league history. At the beginning of the month, the Red Sox held wild-card leads of nine games over the Rays and 10.5 games over the Angels. Both of those leads have shrunk to 2.5 games. No team has ever failed to make the postseason with a lead that large in September.

Plenty has gone wrong for the Red Sox during their current slide. Key injuries and inadequate depth have placed a once-promising season in doubt.

Nowhere has that been more apparent than with the starting rotation, where depth issues have led to a historically bad September.

The Red Sox have just one quality start in their last 15 games, a span in which they've gone 3-12.

After Josh Beckett's late collapse (six earned runs in 7 1/3 innings pitched) Wednesday, Red Sox starters now have a 6.82 ERA in September. That's the worst in the majors this month, and the worst for any rotation in September since the 2008 Tigers (7.12).

History might remember this September for Boston's collapse, but the rotation is achieving an infamy of its own.

This is on pace to be one of the worst months for a starting rotation in Red Sox history. Boston starters never have had a higher ERA in September. Worse yet, it's only ever been higher twice in any full calendar month (min. 20 games), according to Elias. Those would be a 7.02 ERA in August 1997 and a 6.95 ERA in June 1996. (Note: In April 1931, Boston's rotation posted a 7.89 ERA, but in just 10 games.)

The 1997 rotation was mired in a post-Roger, pre-Pedro purgatory. By August, the team was already out of contention and the wheels were starting to come off.

Steve Avery (11.63 ERA), Aaron Sele (8.54) and Jeff Suppan (6.39) were mainstays that month. Tim Wakefield was comparatively solid with a 5.93 ERA in seven starts.

The 2011 edition hasn't been quite as bad this month. Then again, the current woes come in the midst of a pennant race.

Boston played its final home game of the season Wednesday. The rotation finished Sept. 3-7 with a 7.21 ERA at Fenway Park.

Only Jon Lester (3.52) has an ERA below 4.00 this month as a starter. Meanwhile, Kyle Weiland (9.26), John Lackey (10.70) and Andrew Miller (15.63) have combined to start nine of Boston's 21 games.

While the current woes highlight a lack of pitching depth, that was not perceived to be the case at the beginning of the season. With Lester and Clay Buchholz coming off strong 2010 campaigns and Beckett rebounding early, the Red Sox presented a formidable front three. The back of the rotation had proven veterans in Lackey and Daisuke Matsuzaka.

Wakefield, Alfredo Aceves, Andrew Miller and Felix Doubront filled out the roster of potential starters that arguably went nine deep.

Injuries to Buchholz and Matsuzaka quickly brought that depth into focus. Wakefield, 45, will again finish in the top four on the team in innings. A deadline deal for Erik Bedard provided some relief, but he too has battled injuries.

In a season-long quest for consistency, 10 pitchers have made four or more starts for the Red Sox. That's tied for the most in the majors. Only three times in the last 50 years have the Red Sox had more pitchers make at least four starts.

That's led to Weiland starting vital games down the stretch. Weiland's 7.99 ERA would be fifth highest in the last 70 years among Red Sox pitchers with five or more starts. The worst in the span is 9.20 by John Leister -- no relation to Jon Lester -- in 1987.

Meanwhile, Lackey will soon close the books on one of the worst seasons for a full-time starter in club lore. Prior to this season, only one pitcher in franchise history made 25 starts while compiling an ERA over 6.00: Ramon Martinez' 6.13 ERA in 2000. Through 27 starts, Lackey has a 6.49 ERA. Since World War II, only five American League pitchers have had a higher ERA while throwing at least 150 innings.

If Boston does make the postseason, it will most likely mean that the current 6.82 ERA for the rotation in September falls to a more tenable level. According to Elias, the highest September ERA for a postseason-bound rotation was 5.89 by the 2004 Dodgers (lost in the division series in four games). That's nearly a run lower than Boston's current rate.

The rotation is averaging just shy of five innings per start in September. That has taken a toll on the bullpen as well. In nine of 21 games this month, the Red Sox have used five or more pitchers.

Indeed, on some of the rare occasions in which the Red Sox offense has been able to overcome poor pitching, the bullpen has come up short.

Consider that entering the month, Boston was 71-2 when leading at the start of the eighth inning. This month, it is 5-3, having already exceeded that loss total.

Though the bullpen has performed relatively better (5.03 ERA), the staff as a whole is on track for one of its worst months ever. Consider the group of Weiland, Lackey, Miller, Daniel Bard and Dan Wheeler. Those five have combined to go 0-11 with 10.59 ERA in September.

The staff's 5.98 ERA this month would be the highest for the Red Sox in a calendar month since World War II.

Can the pitching get it together to salvage the season? The Red Sox close it out with six road games. They've lost five straight on the road, compiling an 8.29 ERA in that span.

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