Small sample sizes have been, and continue to be, the bane of many a baseball fan's existence. Small sample shenanigans are what led us to wet our pants over Shane Spencer, and declare that Mark Lemke is clutchiest hitter to ever clutch. They're what make relief pitchers so maddeningly hard to predict. They make Chris Shelton seem like a Hall of Famer. They're evil, devious statistical tricks that act like mirages in the searing desert of player analysis.
When a pitcher has a hot stretch, say a month or six weeks, where he's completely dominant, we fantasy owners have to take notice. Say he's like Kyle Lohse early in 2011. Lohse was a scrap heap find reserved only for desperate managers going into the 2011 season. Then he got off to a hot start, winning four games and posting a 1.64 ERA in the month of April. Nothing in Lohse's career indicated that he was going to continue to pitch anywhere close to this well, but fantasy managers in need of pitching were forced to pick him up and ride the hot streak until Lohse turned back into...well, Kyle Lohse.
It never happened. In the past two seasons, Lohse has won 28 games with an ERA of 3.10, an almost miraculous turn for a pitcher who had just been back-end rotation fodder for years. Sometimes the baseball gods like to screw with us, and throw us some small sample size chicanery that turns out to be real. Lohse defied his own history and has remade himself as one of the better starters in the National League (believe it or not).
This season there are several pitchers who have been similarly successful in extremely limited samples. If you nabbed them early, I'm sure you've been the beneficiary of their brief dominance, but are they going to sustain this over the long haul? After the jump, five small sample size pitching stars, and a look at their chances of keeping it up.
Here's one nobody saw coming. Medlen was never regarded as a hot prospect in the minors, starting out first as a reliever and then becoming a starter in 2008. After missing just about all of 2011 with a UCL injury, he started 2012 in Atlanta's bullpen and did a good, if unspectacular, job in middle relief. When Tommy Hanson went down with an injury, the door opened for Medlen to step into the rotation. Medlen didn't need to knock; he bashed the door down with an axe and never looked back. In eight starts, Medlen has been a video game, winning seven times and allowing just five earned runs in 55.2 innings, while striking out 53 (and walking just seven).
Medlen can't be this good, can he? Surely this is just that ol' trickster small sample size messing with our heads again, right? Well, Medlen's microscopic ERA is the result of avoiding home runs, to a ridiculous extent. He's surrendered only three in over 100 innings this year. That won't last, even for a guy who is good at limiting home runs, so his ERA will tick up at some point (his xFIP right now is 3.15).
Here's the thing, though. Medlen's success so far has been based on avoiding walks while missing a lot of bats. He did the same exact thing in the minors; his career minor league K:BB ratio of 4.82 is in the same ballpark as his current 2012 number of 4.45. Medlen will give up some more home runs, but not so much that it will torpedo his ERA so as to make him lose his fantasy value. I like his future as a mid-rotation stalwart, but don't expect to see that number one before the decimal in the ERA for too long.
Griffin is another pitcher who made his way into the major league starting rotation as an injury fill-in. He was initally regarded with mild curiosity by fantasy owners (namely because of his pitcher-friendly home park), but in eleven starts (sandwiched around a DL stint), he's been out of this world. After Tuesday's shut down of the Angels, Griffin is 6-0 with a shiny 1.94 ERA. Is Griffin the real deal, or is he simply taking advantage of the spacious outfield in the Oakland piss hole?
Well, he's been worse at home, so it's not the Coliseum that's responsible for his success. It's mostly that old standby, the extremely low BABIP, which in Griffin's case sits at .238. That's most likely the result of a confluence of Oakland's excellent defense and good luck. No one can sustain that forever, but Griffin's peripherals are consistent with his solid minor league totals, so look for continued success in a larger 2013 sample size, even if it involves an ERA a run and a half higher.
Tillman was a former top pitching prospect who had been killed by some shoddy control in his first three seasons in the big leagues, and from 2009-2011 his major league ERA was an ugly 5.58. This year, though, he's broken through with a career-low walk rate and a career-high strikeout rate. As you might expect, his ERA has plummeted, dropping to a solid 3.39 in 61 innings. At 24, Tillman looks like he's finally coming into his own.
Unfortunately, Tillman's eleven starts perfectly parallel the Orioles' own extreme luck this season. As I mentioned the other day, the Orioles have won a ton of one-run games and have the run differential of a sub-.500 team. When that happens, it's because luck is playing a large part. Tillman is a nice poster boy for this brand of luck, as his BABIP is .249 this year. His improving peripherals are a great sign, but right now his true level is probably at the 4.22 xFIP he currently sports. Not a bad sell-high candidate, especially since Baltimore's recent track record developing pitchers has been a train wreck.
Ever since being taken with the fifth overall pick by the Brewers in the 2004 draft, Rogers has been an injury-riddled mess. Even with the multiple surgeries on his arm, he still came back this season throwing comfortably in the mid-90's with movement, striking out 41 batters in 39 innings. Just when he looked like he might be a gem of a sleeper pick, the Brewers pulled a Strasburg on him and shut him down for the season.
He still has control issues to iron out (3.2 BB/9, even worse in the minors), he wasn't helped by Milwaukee's crappy defense, and he's going to be babied until he can prove he can go five minutes without tearing something in his right arm. However, the fact that he's still able to miss bats after all the injury troubles means he's a nice sleeper pick for 2013.
The smallest of the small samples size heroes here, Archer has made three starts and has thrown 18.2 innings in the majors this year. He has struck out 25 in those 18.2 innings, while allowing just seven runs. He made two spot starts in June as an injury fill-in, then made a very impressive start against the high-powered Rangers last week, striking out eleven batters in seven innings.
Archer was acquired in the 2011 Matt Garza trade and immediately became one of the myriad hard-throwing pitching prospects in Tampa Bay's system. His fastball has averaged 94 mph in his three starts this year, so there's no doubt he can bring it. The concern is that he showed awful control in the minors, so his 1.9 BB/9 in the majors is most likely not for real. He's a keeper league darling, but for the near-term, it's hard to see him with a role in the cluttered Tampa rotation. If he can sustain his improved control for more than a handful of starts (yes, he was awful in the minors, with a 5.1 BB/9), he might wedge his way into a rotation spot should the penny-wise Rays decide not to pick up James Shields's $9 million 2012 club option.