I was very surprised that there was any debate about this, actually, but some Tigers fans believe that Jim Leyland’s decision to pull Rick Porcello in the ninth inning in favor of Jose Valverde last Sunday was the wrong move.
I’m not sure if opponents of the decision simply wanted to see Porcello attempt a complete game, or if they thought that Rick, who had only allowed one hit, gave them the best chance to win the game. Perhaps some simply hate Leyland and think all of his decisions are immediately wrong.
Jeremy Greenhouse, of Baseball Prospectus, came out with a post today showing that Leyland’s decision gave the Tigers the best chance to win the game.
"Between 2000 and 2010, there were over 1700 instances in which a starting pitcher completed eight scoreless innings. In nearly two-thirds of those instances, the starter came back out for the ninth. The team allowed an average of 0.45 runs in those innings. Conversely, when the starter was pulled, his team allowed an average of 0.35 runs in the ninth."
It might be more intuitive to look at those numbers in ERA form. Starting pitchers who had brought a shutout into the ninth had an average ERA of 4.05 (in the ninth inning). Relief pitchers who entered ninth inning after the starting pitcher had worked eight scoreless innings had an average ERA of 3.15.
I’ve never thought of Leyland as a saberist, but he certainly made the correct decision in this particular instance.