Math on the Hernandez + [2009 LF] over Bako + Dunn claim

My claim from the Hernandez piece that his acquisition plus our left fielders may negate the loss of Dunn generated some perfectly justified skepticism over at Redleg Nation. I posted this in the interest of showing my work:

Math on the Adam Dunn claim:

Based on my the article, the projected improvement at catcher, assuming average defense (which is probably overly optimistic…), was 20 runs. So, if Dunn’s loss is negated, the difference between Dunn’s projected offense+defense and the 2009 Reds’ left fielder offense+defense must be 20 or fewer runs.

According to CHONE, Dunn projects in 2009 as a +16 RAA hitter per 150g and a -13 RAA fielder per 150g. That makes him a tad above average as a player overall, +3 RAA. I’ll be the first to admit this seems like a low projection for a guy who’s been a favorite of mine for years, but it actually matches his salary pretty well and CHONE’s as good as it gets in terms of projections. CHONE is pretty aggressive about discounting home runs at GABP when projecting players in other parks, so that’s a big part of why Dunn’s rated so “low” on offense.

Here are some of the 2009 Reds LF options, on a per-season basis in left field:

Dickerson projects as a -15 run hitter and a +3 run fielder = -12 RAA left fielder, 15 runs below Dunn.

Gomes projects as a +7 run hitter and a -14 run fielder = -7 RAA left fielder, or 10 runs below Dunn.

Hairston projects as a -12 run hitter and a +4 run fielder = -8 RAA left fielder, or 11 runs below Dunn.

I still think CHONE is underestimating on Dunn, but even if you give him a subjective 5-run bump on offense the difference between the main LF candidates and Dunn is no worse than the projected improvement at catcher with Hernandez & Hanigan vs. the 2008 catchers.

Now, if you give Dunn a boost, subtract away from Hernandez's value due to shoddy defense, and use a more pessimistic projection of Hernandez's offense, then the numbers start to not add up. Even so, I think Dunn is still probably overrated by a lot of fans who don't take into full account his defensive inadequacies. That's not to say that he's not a good player. Just that he's not one that can't be replaced once you start taking into account his defense.