It has not all been rosy in Jeff Samardzija‘s first season as a major league starting pitcher, but it has certainly been successful. With a 4.06 ERA backed by a 3.54 FIP and 3.59 SIERA, Samardzija has shown the ability to strike out batters at a high rate while getting his walk issues under control. He has battled inconsistency at times, mainly during a stretch in the middle of the season, but overall it has been a rather impressive campaign.
Where Samardzija has derived much of his success is in his split-fingered fastball. He throws the pitch with about a 17% frequency — PITCHf/x says just 13.6% but it also includes a changeup, which he does not throw, at 3.1% — so it is not as if he relies on the pitch extensively throughout each plate appearance. It is, however, his out pitch. Of his 141 strikeouts this season, 58 have come via the splitter. That’s 41% of his strikeouts coming from a pitch he throws roughly 17% of the time, and his strikeout total with the pitch is over double that of any of his other offerings. When paired with a fastball that averages 95 mph, the third highest velocity of any starter in the game, his splitter is a tremendous asset that keeps hitter’s off balance and frequently results in swings and misses.
The pitch averages out at about 86 miles per hour, and only two pitchers throw harder split-fingered fastballs. The splitter essentially is used as a changeup for Samardzija, as it sits just under 10 miles per hour slower than his four-seam fastball. In terms of overall pitch shares, only Dan Haren has a higher rating than Samardzija with a split-fingered fastball. With a minimum of 100 pitches thrown, no pitcher has a splitter with a higher win share per 100 pitches than Samardzija, and he has the third highest win shares per 100 pitches among any pitcher that PITCHf/x believes has thrown a splitter all season — behind only Kevin Millwood (four thrown) and Ubaldo Jiminez (52 thrown).
To say it has been the most effective split-fingered fastball in baseball is not a stretch, though labeling issues do arise as many pitchers use split-fingered changeups, otherwise known as “splange ups.” It seems fair to compare the pitch to changeups rather than simply split-fingered fastballs, since more pitchers throw changeups than splitters and Samardzija’s effectively acts as a changeup. When considered a changeup, Samardzija still sits in the top 10 of win shares per 100 pitches, which better elaborates how effective the pitch has truly been this season.
Overall, hitters have just a .183 wOBA against Samardzija’s splitter this season, despite the fact that he has allowed three home runs with the pitch. The overall success is not limited to just left-handed hitters either, as pitches similar to a changeup normally are for right-handed pitchers. He has a whiff rate above 27% against right-handed batters with a pitch frequency of 13%, while his whiff rate sits above 23% against lefties with a pitch frequency of roughly 20%. In addition to the high whiff rates, he also forces batters to swing at the pitch more than any of his other pitches — with his overall swing rate sitting at 55.2%. His confidence in the pitch allows him to use it in strikeout situations against both lefties and righties, and explains why he has had a successful season to date.
He has battled struggles with tiredness at times, which is understandable given the increased workload, but if he is able to sustain a mid-90′s fastball as a starter over the next few seasons and utilize his splitter with this type of consistency, he could elevate himself to become a top tier starter. He already sits on the first page on FanGraphs (which encompasses 30 players) in both FIP and SIERA, so he is not too far from reaching top of the rotation status as is. Moving from the bullpen to the rotation has caused many pitchers to struggle, but Samardzija has seamlessly moved into the new role and succeeded well past expectations in his first season. With what is likely the top split-fingered fastball in baseball, it is reasonable to expect a similar level of performance or potentially even more success in the coming years.