Contemplating the left field situation

This swing looks awkward, but
Eddie Rosario got a double
out of it at Kansas City.

About a month ago, in discussing the Twins outfield, I noted that Baseball Reference listed Eduardo Escobar as the Twins primary left fielder and declared: "If he's still so listed after the All-Star break, (Paul) Molitor is doing it wrong."

Well, we're at the All-Star break, and Eddie Rosario is now listed as the primary left fielder.

Primary, not regular. Molitor has divvied up playing time in left field to a high degree. Rosario has just three more starts and less than 40 innings more than Escobar. Five players have gotten starts in left, and four of them have more than a dozen (the other two being Shane Robinson and Oswaldo Arcia).

Arcia, of course, opened the season as the regular left fielder. He got hurt and then was optioned out to Triple A Rochester, where he has been on a home-run binge for about a week and a half. Still, he doesn't appear to be on the verge of recall. His flaws -- bad to horrid outfield defense, problems with left-handed pitching -- remain.  I think he's more likely to be traded this month than returned to Minnesota.

Which is, in the abstract, fine by me. (What the return is in such a trade is, of course, the key to whether trading him is a good idea.) I have been claiming for months that outfield defense is a key aspect to the Twins' surprising rise in the standings, and playing both Arcia and Torii Hunter in the outfield corners is detrimental to the outfield defense. Rosario is a much better fielder than either.

But the superior defense comes at a price. While Rosario's batting average (.279) looks good, he has taken just eight walks, so his on-base percentage is barely above .300. He doesn't have Arcia's power either, and his OPS+ -- On base Plus Slugging in the context of league and home field -- is a mere 93, 7 percent below average. And while Molitor may talk up Rosario to the broadcasters as a hitter against left-handers, the early returns on him don't back it up (.239/.294/.304 in his first 52 plate appearances versus southpaws).

This summer's theme of the tension between contention and transition is well illustrated by Rosario's playing time. Keeping Rosario in the lineup is obviously good for his development. But it also probably means having a below-average bat at a position usually counted on for hitting. Rosario has spent a good deal of time hitting fifth, which is not ideal for him or the team.