Since Michael Stutes was called up from AAA, he has worked himself up from filler arm, to hold the fort until Jose Contreas returned from injury, to a trusted mainstay being used in high leverage situations. He's gained quite a following already, especially among the radio talkshow crowd. The questions we must ask though are: How good has he been? and How good can we expect him to be?
To this point, Stutes has been a pleasant surprise coming from seemingly nowhere to help anchor a bullpen which has been quite good compared to preseason expectations. In his 21.2 IP, he has surrendered just 5 ER for a pleasant sounding ERA of 2.08, allowing only 2 HR balls in that time frame. He boasts a LOB% which would cause even Mariano Rivera to glow with envy. Just compare Stutes' 90.5% to the Sandman's career rate of 80.1%. Putting the numbers aside, there seems to be a lot of intangibles to like about this youngster. First off, his age and unexpected success alone make him exciting out of the bullpen. It's fun to be surprised as a fan, and seeing young talent (a rarity on this team) develop is part of what makes sports so enjoyable. More importantly though, he has already come through in some very big games and very big spots this season. He seems to have the composure of a closure and be immune to perturbation on the mound. Judging by his results, he's been a very good player for this team.
With this said, the more important question may be the impact we can expect Stutes to make throughout the rest of the season. Looking at his peripherals, Stutes has a nice ability to miss bats and keep the ball out of play. His Swing Strike percent of 10.6 places him among an impressive crop of relief pitchers. This shows in his ability to generate punch outs with a K/9 of 9.14. These are numbers similar to what Madson has been able to produce in the past. He has done this so far throwing primarily fastball and slider. His fastball has been particularly good to him generating 2.64 runs above average per 100 pitches.
At this point Stutes goes from being exciting to being slightly concerning. When he's not striking batters out, he has a pernicious habit of allowing runners to take to the bases, allowing 5.40 BB/9. This has not yet posed a problem because of his impressive ability to get strike outs. However, going forward walking this many people will most likely keep him from being a true high leverage arm. The trouble doesn't stop there though. When the ball gets put into play against him, it does so in the air with a flyball and line drive percentage of 50% and 19.2% respectively. Despite this, he has enjoyed success this season aided by a .200 BABIP and, as previously mentioned, stranding 90% of his baserunners. These numbers are almost surely going to regress. When this occurs, things could get pretty ugly pretty quickly for Mr. Stutes. If we're to believe FiP and xFip, Stutes has only been a replacement level pitcher, or he has been exactly what he was called up to be.
I don't mean to say that Stutes is a bad pitcher or that he's doomed to failure. There's some small samples at work here, and he could certainly improve both his BB/9 and GB%. One thing that we can certainly count on though would be a regression in his BABIP. If he does not improve his peripherals when this occurs, he should certainly not counted on to be a shutdown late innings reliever. However, as a cost controlled choice for a bullpen that doesn't have much to work with, I'm glad to have him around.