Twins Insider: Another middle-inning meltdown for Diamond

MIAMI – The Twins have a couple of tough roster decisions coming up in the next week or so. One of them involves making room for outfielder Aaron Hicks once he has completed his rehabilitation stint at Class AAA Rochester.

The other will come on July 4, when righthander Mike Pelfrey should be ready to return to the mound after recovering from a back strain. Someone will have to exit the rotation to make room for him.

It won't be Kevin Correia, who has been the Twins' steadiest pitcher.

It won't be Samuel Deduno, who has been effective in six starts since being called up.

It shouldn't be Kyle Gibson, who replaced Pelfrey on the roster and is set to make his major league debut on Saturday against Kansas City. Win or lose, surely the Twins would want to see Gibson make more than one start.

It shouldn't be P.J. Walters, who is coming off a poor outing but is out of options.

That leaves lefthander Scott Diamond, who dropped to 5-7 on Wednesday when he was knocked out in the sixth inning by the Marlins, who won 5-3 to sweep the two-game interleague series.

Diamond has a 1.28 ERA in the third inning and a 3.21 ERA in the fourth but a whopping 12.75 ERA in the fifth.

So, has he pitched himself onto the hot seat?

"Yeah, I think so," Diamond said. "I feel like I've already been on the hot seat. I've got to pitch better, and I think that kind of falls back on not going late in games and having that rough fifth, sixth inning. I feel like I'm showing more consistency. I'm executing pitches better. I have progressed. My numbers haven't shown it yet."

The Twins led 3-0 in the fifth when Diamond gave up a soft single to center to Placido Polanco. After getting Adeiny Hechavarria to fly out, Diamond tried to bust Jeff Mathis inside with a fastball, caught too much of the plate, and gave up a two-run homer.

Then former Twins pitcher Kevin Slowey — who got the win in relief — dropped in a single to left. Justin Ruggiano singled to right and Ed Lucas blooped a single to center to load the bases. Slowey ended up scoring on groundout as Miami tied the score 3-3.

Diamond was allowed to bat in the top of the sixth and came through with a single. That's because Gardenhire wanted him to face the lefthanded-hitting Logan Morrison in the bottom of the inning. That plan blew up, because Morrison, who entered the game 1-for-11 against lefthanders, cracked a single to left. Diamond was lifted for Ryan Pressly, who gave up a home run to Polanco that put the game away.

Gardenhire acknowledged that Diamond was not hit hard but still needs to limit the damage. Also, three of the hits Diamond gave up in the fifth came with two strikes on the hitter, including a 3-2 count on Mathis' home run.

"You got to be able to pitch through it," he said. "You have to be able to finish off a hitter."

Diamond was 12-9 with a 3.54 ERA last season and was one of the positive developments on a 95-loss team. He believes he is close to being that pitcher once again. He said he needs to sharpen his curveball while continuing to execute his other pitches.

He also needs to find a way to get over the hump in the middle innings, or risk losing his spot in the rotation.

La Velle E. Neal III • lneal@startribune.com