Roberto Osuna's Dominance Deserves More Attention

After a slow start, Blue Jays closer Roberto Osuna has been performing just as well as the game's elite relievers.

With the way MLB pitching staffs are constructed in today's game, a strong bullpen -- and in particular, someone who can lock down the ninth inning -- is a vital piece toward ultimately achieving success. That's partially why we've been so enamored with how dominant Craig Kimbrel has been, while Kenley Jansen is having similar results despite leaning so heavily on one pitch. When we think about the game's top closers, they're likely the first two that come to mind.

You know who shouldn't be far behind them, though? Toronto Blue Jays closer Roberto Osuna. If it wasn't for a tough start to his 2017 campaign, a lot of his season-long stats would probably be on par with the game's elite relief hurlers.

A Lackluster Start

For a squad that finished April with an 8-17 record, nothing really went right for the Jays through one month of play. It didn't help that Osuna only saved 3 games out of a possible 6 opportunities while racking up a 5.63 ERA, 1.25 WHIP and a .320 wOBA against in 8 innings of work.

While his peripherals showed that he was a bit unlucky -- he posted a 3.05 SIERA during this time -- possibly the biggest positive was that his strikeout rake settled in at 23.5% to go along with a 0.0% walk rate. However, it certainly wasn't ideal to watch opposing hitters produce a 34.6% hard-hit rate, 40.0% fly-ball rate and 24.0% line-drive rate en route to a .360 BABIP in this admittedly small sample.

Once the calendar flipped to May, though, it's been a much different story for the young right-hander.

Flourishing Ever Since

Osuna has secured all 15 save opportunities in his last 20 innings of work, but what's more impressive is how he's accomplished it. His walk rate since May 1st sits at 2.9%, while his strikeout rate has spiked all the way up to 40.0%. The closer's ERA during this time is just 1.35, but it's also supported with an equally strong 1.64 SIERA and a soft-hit rate (17.5%) that's higher than the amount of hard contact (12.5%) he's allowed.

How do these numbers stack up against the big dudes like Kimbrel and Jansen over the same period of time? Check out the below table where it's all laid out.

Pitcher IP SIERA K% BB% Soft% Hard%
Kimbrel 20.1 0.66 56.5% 4.4% 11.1% 33.3%
Jansen 20.0 0.94 47.1% 0.0% 27.8% 25.0%
Osuna 20.0 1.64 40.0% 2.9% 17.5% 12.5%

Kimbrel and Jansen are still performing better than Osuna in most of these categories, but it's not like he's incredibly far off. It also helps that what he lacks in strikeouts, he's making up for by limiting hard contact.

When we also take Osuna's age (22 years old) and big league experience (currently his third MLB season) into account, it's hard not to get excited about his potential as a consistently dominant reliever moving forward.

The Difference

So, what's been the difference behind this dominance for Toronto's young reliever? His performance improved because the quality of the pitches he's thrown have better.

Of Osuna's four-pitch arsenal, the three he's used the most are his fastball, slider, and cutter. If we use FanGraphs' pitch values as a guide, we can see that each of these offerings have drastically improved since May 1st when compared to how they rated in April.

This improvement has led to some eye-popping changes in his plate-discipline stats. The below table shows the differences between his chase rate (O-Swing%), swings generated inside the strike zone (Z-Swing%), the corresponding contact rates, and his swinging-strike rate (SwStr%).

2017 O-Swing% Z-Swing% O-Contact% Z-Contact% SwStr%
Through April 30th 38.9% 71.7% 46.4% 92.1% 14.4%
Since May 1st 52.5% 76.9% 52.4% 80.0% 21.2%

And, for what it's worth, Osuna's chase rate and swinging-strike rate since May 1st have been better than both Kimbrel's (35.5% and 20.9%, respectively) and Jansen's (45.6% and 18.0%).

Kimbrel and Jansen -- and Aroldis Chapman, when healthy -- will continue to dominate the headlines when it comes to the game's best closers, and rightfully so because they've been disgusting when toeing the slab this season. However, Osuna's performance since May 1st has him rubbing elbows with these two studs.

It'll only be tougher to ignore what he's doing if he's able to sustain this excellence over the next few months.