Should the Twins be concerned?

Jesse Crain is one of the most effective relievers in baseball.  Yet his K/9 has gone from 11.37 in AAA to 3.5 with Minnesota.  His GB/FB ratio is .90.  Does he have any comparables?  Should the Twins be concerned?

1.    pitched more innings than anybody else out of the bullpen
2.    seen 70% of those innings come in a High Leverage Situation (one-run ahead, tie game, one-run behind or tying run at the plate)
3.    failed just THREE!!! times in those innings to prevent the other team from scoring (even if the runner was on base when he entered)
4.    struck out just 14 men (or 3.5 batters / 9 innings)
5.    held right-handed batters to a .208(!!!) slugging percentage
6.    allowed left-handed batters to slug a slightly less ridiculous (but still amazing) .229
http://www.wyoung.net/twins/

The following is copied from the Minneapolis Star Tribune without permission.
Twins' Jesse Crain: No fastball? No problem
La Velle E. Neal III,  Star Tribune
June 14, 2005 TWIN0614

Scouts have walked into press boxes with questions. Reporters have looked at stadium radar gun readings and wondered.
Most importantly, Twins righthander Jesse Crain has thrown a pitch and asked himself: What happened to my fastball?
More than two months later, and after compiling enough shutout innings to make a starting pitcher envious, Crain has answered the question.
Who cares?
Instead of struggling after a change in his delivery decreased his velocity, Crain has embraced movement over power. With a 5-0 record in his second major league season, he has more victories than Twins starter Joe Mays. With a 0.69 ERA, he was the only reliever in baseball who, through Sunday, had pitched at least 14 2/3 innings and had an ERA under 1.00.
"Crainer has been throwing the ball really well for us," Twins manager Ron Gardenhire said.
In 28 games, Crain has given up 13 hits and eight walks. The only reason he has an ERA is because he gave up two earned runs against Milwaukee on May 21. That's it. Opponents are batting .148 with a .159 slugging percentage and .227 on-base percentage.
Crain has stepped up in a season in which the Twins lost Grant Balfour for the year because of Tommy John elbow surgery and top setup man Juan Rincon for a 10-game suspension for violating the league's drug policy.
"We knew coming in what kind of pitcher he is and what kind of pitcher he can be," closer Joe Nathan said. "We knew having him here and getting him confident late in the game is going to be huge."
Not throwing fastballs at 94 or 95 miles per hour no longer is a big deal to Crain, who has developed a sinking fastball to go with his slider and curveball. The sinker comes in about 90 mph and breaks in on righthanded hitters. Once worried about not being able to blow a fastball past hitters, Crain now welcomes contact.
"It's been great," Crain said. "I couldn't throw one in the minor leagues. I couldn't get one of those balls to move to save my life. Coming up here, I've just been working on it, and I get it to move a lot."
But the straight fastball used to be a big deal to Crain, 23, who was drafted in the second round in 2002 and rose quickly through the Twins system. He dominated throughout the Twins' minor leagues. He didn't give up a home run as a pro until last season at Class AAA Rochester.
Crain made his major league debut with the Twins last Aug. 5 and learned early that good hitters could tag his fastball.
The goal was to sharpen his mechanics and learn a sinking fastball. Twins pitching coach Rick Anderson taught him to stand taller in his delivery to get more of a downward angle on his pitches and, consequently, more movement.
That worked, but Crain could no longer push off the mound as hard with his legs, which diminished his velocity. It was a big issue this spring when he reported to camp and could only hit 90 mph on the radar gun.
"At first, I was kind of scared," he said. "I didn't know what I had to do."
Anderson said it forced Crain to adapt. He sharpened his sinker and threw his curveball more.
"It's been a wonderful pitch for him," Anderson said. "He even had a game this spring when he threw a lot of breaking balls. I told him you have to do what you do to survive. He's only been up here a year and has been pitching professional for two years before that, and he is still learning."
Crain still throws a straight fastball. As he's gotten more comfortable with his mechanics, his velocity has begun to creep upward. He's hit 93 mph on the gun several times recently and has touched 94 once, although radar gun readings vary from stadium to stadium. So he can throw two different fastballs, a slider and an occasional curveball at hitters.
The Twins believe their bullpen is as deep as last year's, with Crain, Rincon and J.C. Romero serving as the main setup men for Nathan.
"Pitching at this level is more about getting confidence," Crain said. "Obviously, you belong here or you would not be up here. But to actually feel like you belong here is great. I got on a nice little roll, and I feel like I'm supposed to get these guys out."