Should Francona Have Intentionally Walked Hunter to Get to Guerrero?
The easy answer to this is no. With two outs and runners on second and third in the top of the ninth inning, the Red Sox led by one run. Torii Hunter stepped to the plate against Papelbon and Terry Francona promptly chose to give Hunter a free pass to load the bases. As you know, Guerrero came through with a single to centerfield to drive home the tying and go-ahead run, sealing the Red Sox fate.
While obviously the walk didn’t pay off for Francona and the Red Sox, was it a good move strategically? With runners on second and third, a single most likely scores the go-ahead run. A walk, however, does not immediately hurt you.
However, with the bases loaded, a hit OR a walk blows the lead. While a walk didn't hurt before, it makes a huge difference now.
Taking their 2009 stats as "true" probabilities, let’s look at the probabilities of the Red Sox getting out of the jam with both Torii Hunter and Vlad Guerrero at the plate (in fact Hunter somewhat overperformed his usual year, while Guerrero somewhat underperformed, but let's ignore this for now).
Francona chose to load the bases for Guerrero, so let's examine that first. With the bases loaded and two outs, the probability of the Sox getting out of the jam was simply 1 minus Guerrero's OBP, meaning the Sox had a 66.6% chance of getting him out and escaping with the lead.
How about if they don't walk him? In that case, there is a 63.4% chance of retiring Hunter (1 minus Hunter's OBP). There is also an additional 9.3% chance of walking Hunter and getting to Guerrero anyway. If that happens, there will still be a 66.6% chance of retiring the side without a run. Therefore, the probability of escaping by pitching normally to Hunter is 63.4% + 9.3%*.666 = 69.6%. As we can see, the intentional walk decreased the Red Sox chances of getting out of the jam by about 3%.
The end result is that Francona' walk was an ill-advised move. While Hunter may be a better hitter than Guerrero (though that is debatable), Francona failed, as many managers do, to take into account the fact that a walk hurts much more with the bases loaded than with runners on second and third. While Papelbon blew the game, Francona deserves some of the blame as well.