Brewers reliever Josh Hader is tearing through baseball. The spindly 24-year-old lefty is putting up record strikeout numbers while barely giving up any hits. His numbers are video-game stupid right now: 

18 IP, 4 H, 5 BB, 39 K, 1.00 ERA, 0.42 FIP, 0.50 WHIP

Let's dig in on the strikeout figure. Hader has faced 62 batters this season and he's struck out 39. That's outrageous. In terms of strikeouts per nine innings, it's 19.5. Here are the highest ever K/9 with pitchers who worked over 50 innings in a season. We'll just go with those who finished with at least 15 K/9. 

Pitcher

Year

K/9

Aroldis Chapman

2014

17.67

Craig Kimbrel

2012

16.66

Craig Kimbrel

2017

16.43

Kenley Jansen

2011

16.10

Carlos Marmol

2010

15.99

Aroldis Chapman

2013

15.83

Aroldis Chapman

2015

15.74

Dellin Betances

2016

15.53

Edwin Diaz

2016

15.33

Aroldis Chapman

2012

15.32

As can be seen, Hader is on pace to shatter the record and it would be topping a group of the top fireballer closers of all time. 

Hader didn't come from outta nowhere, even if he wasn't really all that well known among casual, non-Brewers fans. He was a consensus top-40 prospect in baseball prior to last season and came up to make 35 appearances as a rookie. He pitched to a 2.08 ERA, 0.99 WHIP and struck out 68 in 47 2/3 innings. 

He's taken things to the next level this season with much better command and increased use of his downright filthy slider. Check out what it did to one of the best batsmiths in the game on Monday night: 

Joey Votto's knees buckled on an outside pitch! Amazing stuff. 

Through Monday, Hader has thrown his slider 30 percent of the time, up from just 11.2 percent last season. It's been one of the most effective pitches in the majors, too, generally gathering either a taken strike due to the hitter not knowing what the hell to do with it (see Mr. Votto above) or a swinging strike. 

The awkward arm slot from Hader's lanky frame has to be a tough read for the hitter as well, notably for lefties. In Hader's career, left-handed hitters have slashed a dreadful .125/.273/.139 against him. As can be gathered from that line, hoping for a walk has been the best bet, though this year he's cut down on that, too. 

I mentioned the command earlier. Hader missed spots last season on a somewhat regular basis, but that's mostly fallen by the wayside. When he does miss, it's mostly been in the zone, too. Last season, he walked 4.2 hitters per nine innings, but he's trimmed that to 2.5 BB/9 this time around. 

Perhaps the best part of Hader's game? He's a throwback, multi-inning reliever. He has appeared in 11 games to date. Only three of those have gone for an inning or less. Six of those 11 were at least two innings, though. 

Monday night was a thing of beauty and an eye-opener for those who hadn't been paying attention. He held onto a one-run lead for 2 2/3 innings. He didn't allow a single ball in play, facing nine batters. He struck out eight and walked one. 

After the 37-pitch outing, it's unlikely Hader is available Tuesday. Starting Wednesday, though, if you haven't yet had the thrill of watching Hader pitch, find a way to rectify that. He's one of the biggest "must-watch" players in 2018.