What in the World Has Happened to Mike Leake?

Let's go on a little trip back to July 9th of this year. As of that day, Mike Leake had registered two double-digit strikeout games in his entire career, one coming almost exactly a year prior and the other back in 2014. He's a low-strikeout pitcher, but because he doesn't walk anybody, he's able to squeak by.

At that point, he had a 15.0% strikeout rate for the 2016 season, meaning he'd need to face roughly 67 batters to rack up 10 strikeouts in a single game. Seem unlikely? That's because it is.

Then he went and did it.

Twice in a row.

.@MikeLeake8 is only the 12th pitcher to make at least 2 straight starts with 10+ Ks, 0 BB and 1 ER or less. pic.twitter.com/wovv91yfxN
— MLB Stat of the Day (@MLBStatoftheDay) July 19, 2016

Just one question: who is the person masquerading as Mike Leake, and what have they done with the old one?

It's easy to shrug off one high-strikeout start as being a bit of a fluke, but two is a completely different story. What has led to his new-found ace stuff, and can we expect more of it in the future?

Let's take a peek.

Making Junk Look Appealing

Even though Leake's strikeouts didn't pop up until his past two starts, he actually flashed the potential for improvement there back on July 5th. There, he had a swinging-strike rate of 12.1%, his highest since August of last year. As such, in our search for what changed, we'll be including that start, as well.

The first thing you'd look for in a case like this is a change in velocity. If a pitcher's throwing harder, it makes sense that they'd unleash formerly untapped nastiness on their opponents.

For Leake, though, that hasn't really been the case for his fastball. His average fastball velocity his past three starts -- 90.8 miles per hour -- is identical to his mark prior to that. We can check that one off the list of potential culprits.

We can't completely toss velocity aside, though. That was just for his fastball. When we compare his secondary pitches, you start to see a different story.

Those fluctuations aren't major, but when you associate the movement those pitches possess with even the smallest increase in velocity, it's going to make a difference. Leake seems to have noticed these fluctuations because he has altered his pitch selection to favor usage of his amped-up slider.

Leake has shifted away from the stagnant fastball in favor of his off-speed stuff, specifically the slider. That's the type of change you look for in trying to determine whether or not a pitcher's transformation is sustainable, and it's present in Leake's game.

This doesn't fully explain, however, how Leake is getting all of these swinging strikes. Sure, an emphasis on an improved slider will help, but is a half-mile-per-hour difference enough to turn a career finesse arm into an ace-level starter?

In Leake's case, it might be. Suddenly -- as you can see below -- hitters are chasing his pitches outside the zone like there's no tomorrow, and they're doing so less effectively. "Chase Rate" refers to the percentage of pitches outside the zone at which batters swing, and "Outside Contact" is the percentage of pitches they chase on which they make contact. Basically, Leak has these dudes guessing.

The translated version of that table: he's spewing filth, and batters are falling for it. This gives further legitimacy to Leake's recent uptick in strikeouts, making it seem as if we may be seeing a whole new pitcher.

Can He Keep It Up?

There are two separate ways to tackle the Leake conundrum, and they've got two separate answers. No, Leake isn't about to strikeout 10 dudes per game from here on out. Yes, we can expect him to be significantly better than he was previously.

We could have predicted that Leake would see an increase in strikeouts his past few outings simply because of the opponents he was facing. The Milwaukee Brewers and San Diego Padres -- his past two matchups -- have the first- and third-highest strikeout rates in the league against right-handed pitchers. He faced the Pittsburgh Pirates before that, and they're 15th overall, but they have the seventh-highest strikeout rate on the road. Basically, that's a recipe for a really good run, and Leake came through.

That said, this doesn't mean we should completely discount what he did. We saw actionable changes in the way he was attacking hitters, and that means we need to view him through a different lens going forward than we did previously.

Leake's superb command and top-tier ground-ball rate have always made him a guy who was a strikeout pitch away from becoming a quality pitcher. Now, he seems to have found that in his slider with its increased velocity. If he can keep performing at an above-average pace in the strikeout department, then he's going to post some quality numbers the second half of the season.

Based on the team's current rotation, Leake's next two starts will likely come against the Los Angeles Dodgers and Miami Marlins. Those two are radically different from the Brewers and Padres because they own the 16th- and 25th-highest strikeout rates in the league, respectively, against right-handed pitching. Leake's strikeout totals are going to come down in those outings simply because his matchups are not as conducive to them. However, if he can still maintain a swinging-strike rate north of 10.0%, then it may be time to go all-in on the righty.

It's perfectly acceptable to be skeptical about a 28-year-old starter who suddenly transforms into something he has not been in the past. That's what we have seen with Leake his past few starts, so it's justified if you're cautious to fully believe in his success. However, by looking at his velocity and his pitch selection, it's clear he has made a change, and based on the information we have, it seems as if we should expect him to continue to thrive going forward.