Each week on the Statcast™ Podcast, hosts Mike Petriello and Matt Meyers dig into the world of Statcast™ and advanced metrics, exploring the most important topics in baseball through the lens of the groundbreaking Statcast™ technology. Download, subscribe and help others find the show by leaving a rating and review on iTunes or your favorite platform.
It's true that it's only mid-April, still so early in the year that Joe Mauer entered Tuesday hitting .412 and Jose Ramirez .160. There are a lot of unexpected early-season numbers that won't last, because they simply can't. We go through this every year. Baseball takes some time to balance out.
That doesn't mean they don't hold some interest, however -- at least in the sense that digging deeper under the hood of a hot start or a cold one can tell you a little bit about why things look that way right now. At the very least, it's interesting enough to see some names you might not have thought about carrying some massive numbers.
There are five in particular that stood out to us. Which ones will last? 

1. Josh Hader, 61 percent strikeout rate
On Saturday in New York, Hader faced six Mets hitters. The first five -- Juan Lagares, Wilmer Flores, Michael Conforto, Asdrubal Cabrera and Yoenis Cespedes -- all struck out. (The sixth, Jay Bruce, flied out to center.) That seems to have been something of a coming-out party for the second-year Milwaukee lefty, but it shouldn't have been. He's established himself as one of the most high-upside relievers in the game, as he's whiffed 25 of the 41 batters he's seen so far.
If that sounds like hyperbole, it shouldn't be. Since 2008, over 1,200 pitchers have thrown at least 50 innings. Hader has struck out 40.5 percent of the batters he's faced, and that puts him third on that list, behind only Craig Kimbrel and Albertin Chapman. Looking just at the rate of contact inside the zone -- i.e., pure dominance -- he's first.
Hader throws something like Chris Sale's fastball, from a similar low lefty release point, and Andrew Miller's slider. That'll play. It has played.
2. Adam Ottavino, 64.7 percent strikeout rate
Ottavino has struck out 22 of the 34 hitters he's faced, but he's getting there in a different way. Ottavino had previously been a very good reliever for Colorado, of course, but after 2015 Tommy John surgery interrupted his career, he struggled to throw strikes in '17 (5.06 ERA, 6.6 walks per nine) and didn't even make the Rockies' Wild Card Game roster.
Now Ottavino is throwing strikes. He's throwing sliders, more of them than almost anyone in baseball, and they look like this:

Not only that, Ottavino is throwing them in counts that no hitter would expect to see a slider in. For all the money the Rockies spent on relievers Wade Davis, Bryan Shaw, and Jake McGee last offseason, it's their longest-tenured pitcher who has been by far their best.
3. Brandon Nimmo, .590 xwOBA, second best in baseball
Nimmo has only had 27 plate appearances in the Mets' crowded outfield picture, but the entire point here is to highlight interesting small sample numbers and what they might mean. He's not going to keep hitting .333/.481/.714, of course, nor is he going to keep leading the National League in Expected wOBA, as he's doing now.
But we knew Nimmo had showed an elite line-drive rate, a potentially elite batting eye and above-average speed. So far, he's got four barrels, the best possible combination of exit velocity and launch angle, and 15.4 percent of his plate appearances have ended in a barrel -- a top-five rate in MLB.
4. Rick Porcello, .190 Expected wOBA, best in baseball
Porcello may have won the 2016 American League Cy Young Award, but he's never really been considered as a true "ace," at least the same way as current teammate Sale and former teammates Max Scherzer and Justin Verlander have been. In his first three starts of 2018, he's doing his best to change that viewpoint.

To date, there have been 123 pitchers to face at least 50 hitters, and Porcell's Expected wOBA -- a number that includes strikeouts, walks and expected outcomes based on quality of contact -- of .190 is the lowest of anyone. That's in part because he's collected 17 strikeouts against just a single walk and no homers; it's also because his ground-ball rate of 52 percent is well up from last year's 40 percent.
5. Cleveland is baseball's most unfortunate hitting team
You don't need advanced stats to know that the Indians are off to a poor hitting start, since they're hitting a meager .208/.284/.355 to start 2018. It's the weakest line in the game. Is that due to poor luck or poor performance?
The answer, as you'd expect, is a little of both, but Indians are not this bad. They actually have the second-best hard-hit rate of any team in the game, and one of the 10 lowest strikeout rates in baseball. They're making enough contact and they're making hard contact. They're just not finding success -- as the worst-in-baseball .234 Batting Average on Balls in Play would indicate.
The unfortunate outcomes are to such an extent that the 81-point difference between the Indians' Expected wOBA (.347, which is actually above average) and their actual wOBA of .266 is the highest in baseball by quite a bit. On an individual basis, there have been 255 hitters with 30 times up, and Francisco Lindor (expected .438 wOBA, actual .296 wOBA) and Yonder Alonso (expected .442, actual .276) are both among the six biggest underperformers. It'll get better, Cleveland fans. It has to.