Let’s talk about MLB’s ERA leader. He has an ERA of 1.01, a half-run better than any other pitcher. He’s striking out almost five batters for every walk. All but one of his seven starts have lasted at least six innings and seen him give up one run at most.

Excited? This is, of course, 34-year-old Royals starter Jason Vargas. It’s likely that sentence made any excitement evaporate. On Monday’s episode of Effectively Wild, Ben Lindbergh challenged Jeff Sullivan about why he hadn’t written about this six weeks of dominance. Jeff, justifiably, pointed out that Vargas isn’t doing anything differently and he is about as uninteresting as a pitcher with a start this good can be.

Perhaps we’re not being fair to the veteran, just because he’s a veteran who throws 86 instead of a rookie who throws 95. Let’s see if there is anything new about Vargas. (Jeff also begrudgingly noted that he would finally write something about Vargas this week, so here I am, hopefully doing it before Jeff does it much better).

Vargas has thrown very few MLB innings over the past two seasons as a result of Tommy John surgery, but when compared to his previous career marks, nothing leaps off the page. Although his strikeout and walk percentages would be career bests, he hasn’t turned into Max Scherzer or Clayton Kershaw. Vargas has had multiple 7-game stretches with strikeout rates around 22% and walk rates just below 5%, if not better.

The batted ball rates don’t look any different. His ground ball and fly ball percentages are both within a couple of points of his career norms. His line drive percentage of 19.8% is identical to his career rate. Velocity readings for Vargas are different, but only in the direction that you don’t want them to be:

Vargas has not touched 90mph on a single pitch this season, according to Brooks Baseball data. That’s perhaps splitting hairs, given that his high is 89.76 and there are bound to be some measurement issues, but the point stands: Vargas never threw hard, and now he is throwing even less hard. While the pitch usage data looks more varied, upon closer inspection it’s again fairly similar to his last full major league season in 2014:

The changeup has always been his best pitch; by FanGraphs’ pitch values, it has been a clearly above-average offering every season since he became a regular starter in 2010. Using it 30% of the time or so is a great idea, but he was already doing that in 2014. Vargas was a very useful MLB pitcher in 2014, pitching 187 innings with a 3.71 ERA and peripherals that more or less matched the performance, good for 2.2 fWAR.

Thus far, the only obvious difference is that Vargas isn’t throwing as hard as he used to. There are inevitable signs of imminent regression, as you would expect for a pitcher with a 1.01 ERA: the 88.7% strand rate; the 2% HR/FB rate; the .264 BABIP. However, it should also be noted that Vargas has always been good at getting soft contact. Pitchers who barely strike out 15% of batters faced, as Vargas did prior to this season, need to be at least somewhat good at that in order to survive. His career BABIP is .283 and in 2012, he had a .254 mark over 217 innings.

What’s more, the Statcast data actually supports the good results on balls in play. His expected wOBA allowed based on the batted balls he’s given up in 2017 is .249, fifth-best in baseball. When Chris Sale is right ahead of you on a leaderboard, and four of the five names behind you are Kershaw, Scherzer, Syndergaard and Greinke, you’re doing something right (we’ll talk about Trevor Cahill another time). It’s still higher than his actual wOBA of .229, but not so much higher that we should say everything he’s done so far is a fluke.

The new pitch tunnels data over at Baseball Prospectus might offer us one insight into how Vargas might be just a little different. His release point differential is at its lowest since he became a full-time starter – essentially, his release points are more tightly clustered right now than they have ever been, with his arm slot possibly dropping a little since the surgery. In particular, his fastball-changeup and changeup-fastball sequences are more indistinguishable now than they have ever been, not only in terms of release point, but also in terms of how much they break. That might sound like it’s a bad thing – generally we expect more movement, especially late, to be good, and Vargas is not getting as much late movement as he has previously. Leaving out his curve, here’s the vertical movement plus gravity on his other three pitches over the course of his career:

The horizontal movement tells a similar story. Is it possible that the smaller difference in movement is helping Vargas because that, combined with the incredibly consistent release points, is actually making it harder than ever for hitters to tell his fastball and change apart? That would certainly explain this:

Vargas has seen the whiff percentage on his changeup climb by over 4 percent, and his whiffs per swing is now at 45% on the pitch, when previously it had hovered in the 35-38 range. Ignoring the incredibly small sample size of 2016, when Vargas only briefly pitched at the end of the year, it also seems to be helping his fastball and sinker to play up. The pitch tunnel data also suggests a shift in sequencing, particularly in relation to the fastball and sinker, which have been almost completely ditched as a sequence: Vargas has thrown just four sinkers after fastballs all year, and the same for the reverse sequence. He employed those two sequences over 200 times in total in 2014.

It’s incredibly hard to say specifically how hitters are perceiving this altered approach. A reasonable hypothesis seems to be that these changes mean they are struggling to tell these pitches apart, both generating bad contact and causing hitters to make poor decisions about what they swing at. Right now, hitters are batting .138 against the change and .192 against the sinker. All we can say for sure is that Vargas has been one of the most effective pitchers in baseball this year, and it isn’t just luck.

One final piece of data: per Brooks, Vargas has thrown his changeup almost 50% of the time when right-handed hitters are ahead in the count, with his changeup usage in that situation rising from 37% in 2014 to 47% this year – that’s the same percentage as his two-strike usage. That change also corresponds to a 14% decline in fourseam usage with batters ahead. If you command a changeup as well as Vargas does, it shouldn’t matter what the count is.

So Jason Vargas looks more or less the same on the surface, yet there are plenty of ways in which he – or at least his approach – has changed. There are likely numerous aspects of his performance which aren’t documented here which also play into his success, as well as some simple luck – no-one, not even Kershaw, can sustain a 1.01 ERA. The 34-year-old has likely been different every year of his career, but this year his adjustments to fool hitters have been more successful than ever, and hitters haven’t yet caught up. It hasn’t been flashy or distinctive, and that might be for the best. If it was obvious how Vargas was different, it probably wouldn’t be working so well.