Market inefficiency! Walks! On-Base Percentage! Billy Beane! I’m glad we could get that out of the way. Let’s talk about the Oakland A’s now.

With a staff made up of one very good prospect, a once highly touted prospect a rotation filler prospect, and a couple veterans, the A’s have built a top-heavy rotation that sits near the top in most categories, with only three of their five starters really carrying the load.1

As of today, Oakland is tied for second in all of baseball with an ERA+2 of 129 as a pitching staff.3 This has all been done without two of the staff’s younger successful pitching options in A.J. Griffin and Jarrod Parker; both out due to season-ending Tommy John’s surgery.

Though we’ll touch on four of the team’s pitchers, take a look at how the three A’s pitchers with ERAs in the twos are doing it.

Sonny Gray – ERA 2.17 – ERA+ 176

The staff ace, Sonny Gray4 has an ERA+ that puts him in tenth place in MLB and sixth in the AL. Throwing his 94 mph four-seam fastball, topping out at 96 mph 44% of the time, Gray can successfully work off his heater with a good changeup and sinker combination.

This doesn’t make up ground enough to explain such a great pitching performance so far this season. The diminutive 5’11” pitcher’s real put-away pitch is his curveball. Coming in at a cool 81 mph, this bender moves diagonally across the zone to the tune of a 7-inch drop and an 8-inch glove-side slide. Hitters are baffled by Gray’s curve, batting .133 against it with a .146 slugging percentage. With two strikes, the pitch becomes even more deadly, with Gray forcing hitters into an .087 average with a .104 slugging, for a whiff rate of 21%.

Unsurprisingly, armed with a sinker, changeup, fastball (that falls naturally) and a devastating curveball, Gray loves to work down in the zone. Just more than 32% of his pitches come in below the zone, with 53% hitting the bottom third of the zone and lower.

With the big bender being his put away pitch, it is no surprise to see one of Gray’s highest whiff rate zone being down and in to right-handed hitters, 22% of pitchers can’t get a piece of that zone on him.

In just his second year in the league, he only pitched 62 innings in 2013,5 Gray is showing himself to be the ace of the Oakland staff, in practical and scouting terminology.

Scott Kazmir – ERA 2.28 – ERA+ 167

A former strikeout king, a once top prospect, once in line for a massive new contract and never cashing in after years of injuries and ineffectiveness … I’m of course speaking of Scott Kazmir.6 After recouping his value with Cleveland after a year out of baseball, Kazmir is in Oakland on a two-year, $11 million contract.7

The Texan pitcher found his velocity after his fastball dropped to 88 mph in 2011, his final season before taking a year off. At 30 years old, Kazmir is now back to 92 mph on his fastball, but velocity isn’t the secret to his resurgence. While it certainly can’t be discounted, the real secret is his switch from his main fastball being his four-seamer to a sinker. Earlier in his career, Kazmir threw a sinker just about 10% of the time. Now he hurls it 30% of his pitches, flipping the four-seamer down to 19% of his pitches.

With five pitches to use against hitters, plus a show-me curveball, Kazmir has more ability to cut, fade, sink and change speeds in order to get his opponents out. When he gets two strikes on the batter, Kazmir turns to his mean lefty slider to a tune of 31% of two strike pitches. In that situation, hitters are swinging through the pitch at a 21% clip.

It isn’t realistic to expect Kazmir’s home run percentage to stay at 1%, But with an extreme ground ball to fly ball ratio of 1.11 GB per FB, the numbers match up. This is a new trend for Kazmir as he spent his entire career with roughly a 0.65 GB/FB. It’s not likely a sustainable one, but it’s impressive nonetheless.

It may come as a surprise that Kazmir has an extreme reverse-platoon split so far this season. Righties are hitting just .190/.242/.301 while lefties are hitting a solid .302/.348/.326 against him. Reverse-platoon split studies are still being done and they are becoming more popular, but some early suggestions indicate that vertical movement pitches (changeups, 12-6 curveballs)8 are better against same-handed batters, while horizontal movement pitches (sliders, two-seam fastballs) are better against opposite handed batters.9

This might not quite be random, though it very very10 likely is, if the information from FanGraphs is to be believed, then Kazmir could be artificially working his reverse-platoon split by throwing his changeup and curveball more.11 While I’m struggling for a source to provide at the moment, scouting types often cite the need of a pitcher to develop a changeup in order to get same-handed pitching out at the MLB level. Kazmir throws his change more than 27% of the time against righties and under 2% of the time against lefties. The fade and drop of pitches with arm-side run make them harder for same-handed hitters to line the bat up to the ball.12

The low slugging is no surprise though as Kazmir has shown an extreme ground ball tendency this season, but the home runs will come if he lets lefties hit him this well going forward because the righties will come around.

With just nine walks allowed on the campaign so far, Kazmir keeps runners off the bags with the eighth best WHIP13 among starting pitchers in MLB. That puts him at second best in the AL, behind only Masahiro Tanaka who is at 0.974.

Kazmir seems ripe for some regression because of his extreme differences in his career GB/FB split and insanely low HR%, but that doesn’t mean his numbers won’t be still solid once he levels out, these innings are in the bank after all.

Jesse Chavez – ERA 2.44 – ERA+ 156

Though Kazmir is a resurrection story because of his career and injury history, Jesse Chavez14 is the biggest surprise of the bunch. Currently the best strikeout artist of the three, Chavez is 21st in MLB and 11th in the AL with a strikeout percentage of 24.6%. While higher than his career average of 20.1% and the highest SO% of his career, it isn’t so far out of whack that it can’t be sustained at a relatively high pace.

The two secrets to Chavez’s success, from a results standpoint that is, are his career low 5.8% walk percentage and his matching 5.8% extra base hit percentage, second lowest of his career. Though not as low as Kazmir’s home run percentage, Chavez still sits at a very good 2.4%. While the friendly pitching confines of Oakland’s Coliseum certainly have helped these pitchers keep the ball in the park, Chavez has a lower opponent’s slugging percentage, .292, on the road than at home, .354.

Since joining the A’s, the lanky righty has quickly decreased his dependence on the four-seam fastball. It was originally his main pitch, then a variant pitch, now it’s become just a show me pitch, with Chavez only throwing it 3% of the time this year. He has greatly increased his sinker and cutter use, with the two pitches making up 67.2% of his total pitches.

While his 15% use changeup is his best swing-and-miss pitch (a 25% whiff rate), all of his pitches are missing bats at respectable rates when the batter is down to one strike left. Chavez’s curveball show such a stark speed change from his sinker, 92 mph to 76 mph, that it’s become his best whiff rate pitch in all counts.

Keeping the ball low, as everyone knows, is the secret to keeping the ball out of the bleacher seats. Chavez is keeping the ball down with his variety of sinking/breaking pitches. It may not be as extreme as Sonny Gray’s low-ball efforts, but it’ll do.

Though less reliable, Drew Pomeranz has recently taken over for an ineffective Dan Straily in the starting rotation. After a successful stint in the bullpen, Pomeranz has an ERA of 1.14 and an ERA+ of 337. It’s a small sample and certainly not sustainable. Pomeranz’s stats are that of a pitcher in April. With just two starts under his belt and a handful of appearances out of the pen, the story of Drew Pomeranz has yet to be written, but the ability is there.

Scott Kazmir is certainly a name that rings bells and Sonny Gray is a prospect junkies wet dream in the build of a Tim Lincecum, but the A’s pitching staff is getting it done as one of the best rotations in the league … without the likes of a Clayton Kershaw, Justin Verlander (or Max Scherzer in Detroit’s case), or Jose Fernandez (prior to his TJ announcement of course, terrible). Pitching like this is how you have a 25-16 record and a three-game lead in the AL West.