Something isn't right with Scott Diamond.

The man who was supposed to be a calming force in the Twins starting rotation has become a punching bag for opponents. He hasn't won a game since June 20th and he gave up four runs in a little over five innings in that start. A sophomore slump has hit Diamond hard and it's tough to know what the Twins can do about it.

Since June 9th, Diamond has struggled mightily on mound. In his eight starts during that stretch, he has failed to make it into the fifth inning in four of them including the last three. He's given up 30 earned runs in 40 innings for a robust 6.75 ERA. Overall, opponents are hitting .312/.369/.547 against him and he has given up more than a home run per game in his last eight starts. These numbers are tough to look at but it might have been easy to predict that there would be some struggles.

There were signs of something wrong at the end of last season. Diamond was terrific in the first half by posting a 7-3 record and a 2.62 ERA with a 1.18 WHIP. There was some talk of Diamond making the All-Star team because of his strong pitching performance. The second half didn't go so smooth. His record dropped to 5-6 and his ERA expanded to 4.31 while his WHIP went up to 1.30. The end of his rookie season couldn't get there fast enough.

One interesting statistic to look at for Diamond is his batting average on balls in play (BABIP). If you aren't familiar with this statistic, here is a brief introduction lesson. BABIP tells us how many hits a pitcher is giving up when the ball is put in play. In this case, "put in play" means the ball stays fair and in the ballpark, rather than the play resulting in a walk, home run, hit by pitch or error.

Last season, opponents had a .292 BABIP versus Diamond. This mark ranked him in the top 20 in the American League. So far this season, Diamond's BABIP has risen to .319, the 43rd best mark in the AL. The only qualified AL pitchers with a worse BABIP are Bud Norris, Corey Kluber, Justin Verlander, and Joe Blanton. Most fans might think it's good for a pitcher to be on the same leader board as Verlander but that's not the case in this situation.

Another area where Diamond has struggled has been his ability to limit damage when runners get on base. In 2012, Diamond was able to leave runners on base at a 73.3% mark. This ranked him 16th among AL starting pitchers and ahead of players like CC Sabathia, Yu Darvish, and Matt Moore. So far in 2013, Diamond has the third worst LOB% in the AL at 67.4%. The only pitchers with a worse mark are Jerome Williams and Rick Porcello.

Let's take a closer look at the last two starts from Diamond and try and find where some of his struggles might have originated. Take a look at the strikezone plot map from Diamond's start on Sunday versus Cleveland. As you can see, there are a lot of pitches in the zone and a lot of balls left up. This looks a lot different compared to his previous start in New York.

Against the Yankees, Diamond seemed to have a different game plan or he was continuing to struggle with his control. Most of his pitches were well out of the zone and it's hard to believe he got anyone out with this kind of control. He might have been trying to avoid batter's hitting it into the short porch at Yankee Stadium but this might also show why he was only able to last 3.1 innings.

The Twins need to do something with Diamond. A trip to Rochester might be in order to get his head and control back where it needs to be. Fellow Canadian left-hander Andrew Albers also started on Sunday for the Rochester Red Wings. It could make sense to flip-flop these two men for their next few starts. Albers has a 10-4 record on the season and a 2.97 ERA.

Diamond needs to get fixed and this might be the right time for him to be demoted.

Could be mechanical after his elbow thing last offseason. Or it could be the league caught up with him after last year's ASB. Or it could be mental. Let me know if any of this is helping.

Diamond has lost 1 mph on his FB (89 mph in 2012, 88 mph in 2013).

I think the bigger change has been that he has been throwing his curveball a lot less and his fastball a lot more (2012: 60%FB 29%CB, 2013: 64%FB 24%CB). For a soft-tosser like Diamond, that's probably a bad thing.