There has been talk that Jason Bay has come back to the Red Sox asking if they could still resign him. Obviously there are a ton of problems with resigning him, but that isn’t what I wanted to discuss here today. There are a few of things to take into account though if Bay was to become the Red Sox designated hitter.
The first is when we discuss designated hitters we are talking about someone who has no need for defensive value so his level of “average” and “replacement” is very different. This has been articulated many times by Tom Tango, but replacement level at DH is actually average. Or essentially the player available as a replacement is more likely to be a league average hitter.
This effect is why the DH has such a large positional adjustment at -17.5. The league average DH needs to be 20 runs better with the bat than the league average hitter to make this up. Using this positional adjustment we can start to see how bad a defender needs to be before they would be a better player at DH.
You may have noticed that the positional adjustment does not equal the replacement level adjustment (-22.5). That difference of 5 runs or 0.5 wins is also from Tango based on the difficulty players find in switching to DH. The average player will lose about 5 runs in value just by this move and is accounted for this way. This loss of value is considered an effect of having to play from the bench for the whole game.
How will this all effect Bay though? The good news is that he plays in left field, which already has the second largest negative positional adjustment. At -7.5 in left field he will only lose another 10 runs moving to DH or one win. That may seem like a lot, but let’s not forget how poor Bay has been defensively in his career.
His career UZR/150 in left field is a -8.0, but has been greater than -10 for 3 straight years. That is enough to make the move to DH look interesting to any team in the AL that signs him.
Obviously the Red Sox don’t have a hole at DH in 2010, but with David Ortiz up after this season they would after that. The problem of course is that we don’t have anywhere to hide him now for 2010. The Red Sox are not paying Mike Cameron to only be used against left handed pitching, but I’m diving into the topics I said I didn’t want to cover here.
Let’s take a look at what Bay would look like if he was headed to DH in 2010 here or somewhere else. His CHONE projection is for 22 batting runs and Bill James is a bit more optimistic at 27 batting runs. Let’s run through the projections at LF and DH using the slightly more optimistic numbers.
Batting Defense Replacement Positional RAR WAR LF 27 -11.8 22.5 -7.5 30.2 3.0 DH 22 0 22.5 -17.5 27 2.7 (using fan projections for defense)
I’m sure this isn’t what we were expecting when we entered this exercise, but he is essentially the same value to the team. Even if we ignore the 5 run drop at DH he is only going to 3.2 WAR. This makes Bay essentially the same and wouldn’t be worth moving to DH for the time being unless you have a better defender.
So where does this leave Bay as a potential player for the Red Sox? Probably no better or no worse. His defense is probably as bad as it’s going to get and as long as his bat maintains 25-30 runs in value there is no big rush to move him to DH. That of course doesn’t make him likely to be signed for 2010 with our full outfield and DH.