In what could be the first of many trades with fantasy implications this week, the Diamondbacks and the Angels swapped starting pitchers. Dan Haren heads to Anaheim in exchange for Joe Saunders and prospects. While the merits of the deal for both sides have been covered by Christina Kahrl and Kevin Goldstein, we can take a look at how this changes the fantasy value of the two pitchers with the league and park switch.
Dan Haren was covered in this space nearly two months ago due to uncharacteristic first-half struggles. Much of the blame was on that of the defense behind him as well as his home park, Chase Field, as a bout with homeritis was not helped by an offensive-oriented environment. He is still giving up the long ball at an alarming rate of 1.5 per nine on the season, which is down 0.3 per nine since June 4, so things have started to even out at least. Moving to the AL does put him in the tougher league, but also keeps him out of Chase. Given his lofty strikeout totals and near-invisible walk rates, ditching the long ball issue makes Haren into the ace we expected him to be (though, this being Dan Haren, we can always worry about the second half being worse than the first).
Haren's BABIP in Arizona was .350, which isn't a surprise when you consider the D'backs have converted just 67.7 percent of balls in play into outs, the third-worst rate in the majors. The Halos haven't been that much better, coming in at #20 with 68.6 percent converted, but a slight improvement to go along with fewer homers should help Haren's actual ERA look more like his SIERA. Haren isn't as dependent on his defense as many pitchers anyways, given he has been striking out 23 percent of his batters (one per inning).
If you haven't dealt Haren yet, then hold onto him, because the team switch should benefit him, assuming the second half struggles of the past don't show up once again.
On the other hand, Mr. Saunders may be in for a bit of a shock. The league average strikeout rate is 7.0—Saunders is whiffing 4.8 per nine. He leans more groundball pitcher than not, but is closer to average than extreme. This year he has a 1.1 G/F ratio (average as can be) but generally he is in the 1.2-1.3 range, which isn't that much more than average anyways. He gives up home runs at a league average rate, and given his flyball rates should see more pitches end up in the bleachers by moving to Chase. Despite the Angels defense, he posted a BABIP of .305 on the year—that's a bit lucky given the fielders behind him, and there's a very real chance things will change when he plays in front of one of the league's worst defense (just ask Dan Haren how that went for him).
Saunders value was limited outside of AL-only leagues, and the same will now apply to NL-only leagues. Given he offers little in the way of help for your strikeouts and WHIP, and may take a beating on homers relative to what you're used to, this value is lower than it was. Throw in the fact that the Diamondbacks have a horrific bullpen and can blow what leads Saunders is able to gain, and he becomes almost a non-factor outside of contributing innings to you. The fantasy baseball equivalent of an innings eater isn't very attractive, especially if you just lost Dan Haren in an NL-only league and need to find a suitable replacement.