(Toni L. Sandys/The Washington Post)

The Nationals are Dan Haren’s fifth major league team and his first in the East. His move toward the rising sun got off to a rough start, and it took until May for his ERA to drop below 5. Inconsitency in May was replaced by struggles in June, with a trip to the disabled list shortly after the solstice. The man counted on to be the fifth starter for a contending club had run up an ERA of 6.15 over 82 innings. He had more outings that ended before the fifth inning (4) than lasted into the seventh (3).

Since returning on July 8, and further benefiting from some extra rest around the All Star Break, Haren has posted a 2.40 ERA in 30 innings. His last two starts were seven innings long and his ERA is down a full run, his best mark since May 30. This begged the question: What changed?

First and foremost, we can assume he’s in better health now than he was when he went on the DL. Yet you won’t notice when you check the speed of his pitches, with everything down a hair (0.3 mph off his fastball but 0.7 mph off his sinker). Or his walk rate, which has skipped up but is still in the “hey, that’s good” range (1.4 to 2.4 per 9 innings).

The big improvements have come on missing bats (SO per 9 IP 7.3 before the DL trip, 9.6 since) and giving up home runs (1 every 4.3 innings before the DL, 1 every 15 after). That drop in home run rate is also reflected in his SLGCON (slugging on contact) allowed. Haren gave up a meaty .684 before the DL, thanks in part to those home runs, but has kept the ball in the park and the SLGCON down to .413 since coming back.

This is all a welcome relief, but what’s really different? I’ll let someone else analyze the lineups, but Haren’s opponents have not taken advantage of the platoon against him since his return. He faced 48 percent left-handed hitters before the injury shut him down, but just 27 percent since.

This advantage is behind some, if not most, of his improvement. Underneath the improved K rate is an improved whiff rate (he’s not getting any more called strikes than before). His whiff rate splits are roughly same pre- and post-DL, so the “improved” whiff rate can be attributed to the lack of left-handed batters rather than a specific improvement by Haren. Righties have whiffed at a rate around .26 and lefties around .15 when facing Haren this year — before and after the DL stint.

Let’s pause for a moment. Things have been better, Haren’s healthier and working deeper into games. The outcomes have improved. While the walk rate has gone up, it’s still in a happy place. His K rate is something of a mirage due to predominance of right-handed batters. But there’s more good news. How good depends on how much control pitchers exert over batted ball outcomes.

Righties had a good early season against Haren with the long ball. The typical right-handed starter, and Haren himself, usually give up 0.08 home runs per non-infield fly in the air (fly balls plus line drives) when facing right-handed hitters. They’ll usually give up a SLGCON around .500, although Haren could be expected to allow something closer to .520 based on recent performance in the same matchup. Haren’s pre-DL “HR per FB+LD” was a frightening .17. Double the expected rate. Lefties were having success, but they actually had a lower HR/FBLD (.09) and a lower SLGCON (.608 vs. .755) than the righties.

Since The Return of Haren (Now with less pain) the few lefties he has faced have mustered a measly .250 SLGCON. That won’t last, but at least the rates he has against right-handed hitters post-DL are right on target (.07 HR/FBLD and .511 SLGCON).

Behind the numbers, which are behind some other numbers, are actual pitches going to actual locations. As the following charts illustrate, Haren is avoiding the inner half against lefties and going more down/down-away than down/down-middle as he was before the DL trip against righties. If this improvement in command or change in approach is behind the better outcomes on batted balls, the final weeks of the season could continue to be productive for Haren.

vs. RHH, before DL:

vs. RHH, after DL:

vs. LHH, before DL:

vs. LHH, after DL:

Harry Pavlidis is the founder of Pitch Info. Follow him on Twitter: @harrypav.