You might remember in December I did a rough calculation based on the big four's projected IP per start to determine about how much of the bullpen we could expect to see this season. This was my conclusion:
Since we don't yet know for sure who the fifth starter will be in 2011, if we are to account for the remaining 36 games in the season by assigning them to an imaginary starter that pitches the 2010 league average 5.91 innings per start, we get an additional 212.66 IP, which brings the projected team IP/S to 6.87. If we assume the entire Phillies pitching staff combines for 1458 innings pitched (or 9 IP per game), this means the Phillies bullpen will log approximately 344.33 innings in 2011.
At the time I wrote the post, the fifth starter was much less clear than it is today. Thus, I substituted the league average 5.91 innings per start for the remaining 36 games to be pitched by our not yet determined fifth starter By now the dust has settled and it is becoming more and more likely that Joe Blanton will indeed be the fifth starter. How does this change my conclusion from December?
Well, Bill James projects Joe Blanton to pitch 192.0 innings in 29 starts (6.62 IP/S) in 2011. If we add these 192.0 innings to the 901 innings the top four members of the rotation are expected to pitch, we get a total of 1093 innings pitched in 155 starts (or 7.05 IP/S) for the rotation.
This still leaves seven starts to be picked up by some combination of spot-starters (most likely Worley and/or Kendrick). Let's substitute the league average 5.91 IP/S for these seven starts, which gives us an additional 41.37, bringing our totals to 1134.37 and 7.00 IP/S. If we still assume that the pitching staff will throw 1458 innings in 2011, that means that the bullpen can now be projected to throw about 323 and 2/3 innings. In other words, Blanton is projected to save the bullpen more than 21 innings over a replacement level starter. On the outside chance that Lidge, Madson, and Contreras manage to combine for 200 innings, that would leave just 123 and 2/3 innings to be split by the rest of the pen.
Of course, the news of Adam Wainwright's injury today should serve as a sobering reminder for Phillies fans of just how thin the line is between a "sure thing" ace and a Kyle Kendrick, and projecting players is a fundamentally imperfect business, but the prospect of seeing so little of the back-end of the bullpen this season (especially in high-leverage situations) is something to be excited about.