August and Everything After: Jake Arrieta Looks to Extend his Month-Long Dominance Down the Stretch

Jake Arrieta just allowed 4 runs on 19 hits and 9 walks. That would be a really bad game. Well, actually, it’d be a really weird game if you surrendered all those baserunners with only 4 runs to show for it. In any case, those numbers weren’t accrued in a single game, or even two or three. No, that was Arrieta’s 5-start month of August, a run that has further elevated him into the conversation with the elite pitchers in the game.

I know pitcher using a pitcher’s record as a significant measure of his performance is a bit gauche these days, but there’s a funny thing about having a “W” next to your name: it means your team won. That means Arrieta’s 5-0 record on the month is a decent representation of what he’s been able to do for his team. Each time he took the bump, it was deemed a “quality start,” which means a pitcher went at least 6 innings and allowed 3 or fewer earned runs. Arrieta’s streak in that category now stands at 13.

In fact, of the 4 runs the Cubs’ ace allowed, only 2 were earned. And both of those came in his start against the White Sox. In 3 of his August starts, Arrieta didn’t allow a single run to score. It helps when you don’t allow any home runs, something the Braves found out all too well. Of the 15 balls they put in play against Arrieta on 8/20, none got off the ground. That’s, um, pretty impressive. For the sample, opposing hitters got only 36.5% of balls in play in the air (21.2% LD, 15.3% FB).

Much of what makes Arrieta so good is the sharp movement he gets on his pitches. He’s able to fool hitters into thinking balls are strikes and vice versa. Consider that the average major leaguer swings at 31.3% of the pitches he sees outside the zone. That same player swung at 34.2% of pitches Arrieta threw off the plate. And while batters, on average, swing at 67% of the strikes they see, they only offered at 62% of Arrieta’s strikes.

Those are significant differences when you consider that this 5-game sample alone featured 199 balls and 341 strikes. In most cases, swinging at a pitch outside the zone will result in either no or weak contact; Arrieta induced 6 more such swings than the average. Conversely, he threw 17 more called strikes than an average pitcher would have gotten. All in just 5 games.

Oh, another point about the type of contact guys are getting off of Arrieta: 30.7% of it was soft, as compared to an MLB average of only 18.5%. Combine that with a 63.5% ground ball rate and you see why batters had a measly .216 average on balls in play vs. Arrieta as compared to a league-wide mark of .299.

While ERA has fallen out of favor as the go-to stat for pitchers, there’s no denying that the 0.54 Arrieta compiled in August is reasonably indicative of his dominance. Even removing some of the good luck from the equation, we find a 2.26 FIP and 2.82 xFIP that are quite good. You know what else is good? Three of the starts in this group came on the road; I said it a short while ago in another post, but Arrieta is a steady as they come in terms of home and away splits.

Some have questioned the newly-christened ace’s ability to keep up the pace of a season in which he’s already exceeded his career high innings-pitched total of 156.2, which was set just last year. And that shattered the 119.1 he tossed for the Orioles in 2011, though if you look at total professional innings in a season, Arrieta compiled 173.1 between AAA and the Bigs in 2010. In any case, his 174 this season is still a high and he’s got another 5 or 6 starts to go.

But anyone questioning this man’s stamina or drive doesn’t know a thing about Jake Arrieta and what he’s about. A tireless workout fiend, Arrieta is committed to keeping his body in optimal shape to take the mound every 5th day without fail. It’s not just about being able to push physical limits either; Arrieta’s mental game is as sharp as anyone’s and you know he’s getting fired up to get a shot at the postseason.

There’s good reason to believe August was less an aberration and more a springboard to a stretch run that could lock up a playoff spot and even have the Cubs flirting with a division title. It’s going to hard to top this most recent month, but Arrieta’s numbers have been improving as the season has gone along. His May ERA/FIP split was 3.99/3.18; in June that split was 2.45/2.73 and in July it was 1.91/2.21. I guess this means he’s on pace to allow 0 earned runs in September.

Unrealistic as that goal might be, it sure looks as though Arrieta is getting stronger as the season goes on. Baseball is a grind, both mentally and physically, so the player who can maintain an edge on both fronts is going to have a huge advantage over those who are burning out. This is where I think Joe Maddon’s unseen influence plays a huge role. Arrieta hasn’t been happy with going only 6 innings in each of his last two starts, but Maddon is trying to bank those frames for later whenever he can.

The veteran skipper is also fully cognizant of the overall psyche of his team, constantly shifting players around in the batting order and the field to keep things fresh. Even the mainstay players are getting days off, breaks designed to rest the mind as well as the body. You see, Arrieta’s not the only Cub entering virgin territory when it comes to the time he’s logging. These rookies have never been a part of such a long season, and certainly have never had this much pressure or publicity.

As it stands right now, Jake Arrieta leads the majors in wins with 16. But as far as he and the Cubs are concerned, the only wins that matter are the ones that come on or after October 7th. And the way he’s pitching right now, there’s no reason to believe Arrieta won’t be able to make that happen.