Let’s talk about Jeff Samardzija. As a lifelong Cubs fan, I’m all too familiar with him, both highs and lows. He was the ordained ace for a lot of Chicago’s bad seasons, until he turned down a 5-year contract in the neighborhood of $85 million and ended up on the South Side by way of Oakland. While there, he logged lackluster numbers, gave up an AL-leading 29 home runs, and got generally shelled to the tune of a 4.96 ERA. Over the offseason, he found his way to San Francisco for their customary even-year title run. He was a risky acquisition that many fans might not have had much faith in, or even scratched their heads over. Then, he started playing. Shark has been fantastic so far in 2016, and there’s at least one big change that seems to be a large part of it. Let’s take a closer look.

For reference, here’s a standard stats comparison of Samardzija’s 2015 and 2016:

IP ERA K/9 BB/9 HR/9 xFIP 2015 214.0 4.96 6.86 2.06 1.22 4.31 2016 56.1 2.88 7.51 2.08 .64 3.41

Reference: If you don’t know xFIP, it’s Fielding-Independent Pitching with ballpark size factored in, so it’s less forgiving in pitcher’s parks and more so in hitter’s parks.

Let’s get the easy things out of the way. First, we all know that AT&T park is a pitcher’s park. It’s huge. That’s why I used xFIP above, and it still doesn’t completely explain that massive statistical difference between 2015 and 2016. Additionally, Dave Righetti is well-known for his ability to work with flyball pitchers and mold them into excellent Giants players. On top of that, the Giants’ defense is significantly better than the White Sox defense, which saves some runs (that’s why I used an FIP stat at all). Shark has lived his entire career in situations where he just never got the run support, with a solid career FIP. However, not only is he better-supported this year, but he’s pitching better.

Samardzija’s HR/9 is at a career low since 2011, basically half what it was this year. His K/9 is back up, and he’s generating a lot more ground balls: an absurd 50.6% this year versus 39.8% last year (34.8% career average). Question is, where are all those weak grounders coming from? He’s throwing around the same amount of fastballs, around 42%, which is traditionally his most valuable pitch. He’s throwing his least valuable pitch, his curve, a bit less. That helps.

The real key here? His cutter.

Samardzija’s most effective pitch by runs above average is his slider, but he’s reduced its usage in favor of a cutter that he’s used increasingly over the years. That cutter has been around average by value every year until now. It’s his second most effective pitch in 2016, and he’s throwing it a lot. Shark throws his cutter in 2016 a staggering 37.5% of pitches. Not just that, but it’s better than it was last year. Look at the contact map for it last year versus this year, per FanGraphs. Pay close attention to the mid-left side and edges, since Shark throws right and cutters break glove-side. Hitters are getting significantly less quality contact on that pitch when it lands where it’s supposed to, and the edges are ice-cold. If you hop over to the heatmaps by batting average, it shows the same result. Not only are hitters getting a hold of less of Samardzija’s cutter, generating a much smaller heat zone, but they’re getting hits off of it. In 2015, the hottest gridpoint on the cutter inside the zone was a BA of .247 on the middle-inside (for righties). This year, it’s .205.

Part of this can be attributed to a better pitching coach, as noted above. Maybe he told Shark to go guns-free on the cutter, maybe they just cracked the code. Whatever happened, it isn’t just Samardzija’s new surroundings that make the difference though. He’s throwing the ball better, in large part due to high usage of a dangerous breaking ball that’s peaking in effectiveness. His cutter could fall off by quite a bit over the season, and still be a great pitch. If nothing else, it’s just another twist to throw at batters to dilute his pitch pool. Either way, it’s a huge part of his success in the Bay Area so far. If the Giants can continue to get this production from him, he might come up as one of the best mid-rotation pitchers in baseball, with top-two numbers. That bodes well for San Francisco.