The reigning National League Cy Young Award winner is back for more.

Mets right-hander Jacob deGrom has been great this season, but a couple of early-season starts in which he allowed five-plus runs pushed his ERA to 4.85 entering May, despite opening the year with back-to-back scoreless outings. His ERA was at 3.98 through May 17.

But with small samples and early-season hiccups behind him, deGrom now has a 2.77 ERA and finds himself right back in the mix of the NL Cy Young Award race heading into his start on Sunday afternoon against the Nationals at Citi Field.

With Max Scherzer on the injured list and Hyun-Jin Ryu returning from the IL on Sunday, it appears that the time is now for the reigning Cy Young winner to make his push.

deGrom’s Cy Young pitch

The pitch that’s been key for deGrom? His slider. His speedy, speedy slider.

deGrom has a 92.5-mph average velocity with his slider, the highest average velocity for any pitcher’s slider in 2019. What’s more, it’s a full mph faster than the next fastest pitcher’s average slider velocity -- Zack Wheeler, at 91.5 mph.

Just how fast is that? Well, it’s faster than the average fastball velocity of 204 pitchers this year (minimum of 100 fastballs thrown).

Success with the slider isn’t new for deGrom. Last year, en route to his NL Cy Young Award, deGrom held hitters to a .187 average in at-bats ending on the pitch, with a .196 expected batting average, struck out 81 batters and got whiffs on more than 35 percent of swings against the pitch. In 2018, he used his slider 24 percent of the time.

This year, that usage rate has risen to 31 percent, and the average velocity has risen to the aforementioned 92.5 mph, from 91.1 mph in 2018. None of those changes have sacrificed the effectiveness of the pitch in any way. Opponents are hitting .185 in at-bats ending on his slider this year, with a .190 expected batting average, both slightly lower than in 2018. The whiff rate is up ever so slightly, and deGrom is just eight slider strikeouts away from tying his 2018 total.

In other words, one of the best pitchers in the game took his best pitch other than his fastball and made it even more unhittable.

The slider got him back in the race

deGrom’s slider has really ramped up since he hunkered down following that May 17 start in Miami, when he allowed seven runs (six earned) in five innings. In 14 starts since, he has a 2.08 ERA and has allowed more than two runs just once -- and in that start, he only allowed three.

Through May 17, deGrom was using his slider 25 percent of the time. Batters had a .221 batting average in at-bats that ended on the pitch, and a .210 expected batting average. That all sounds pretty good, but it was about to get a lot better.

Since his subsequent start on May 22, deGrom has been using his slider 32.5 percent of the time. Opponents are hitting .165 in at-bats ending on the pitch, with a .179 expected batting average. In other words, not only are batters getting fewer hits off the pitch, they’re making worse contact, too.

Something else that’s up? His whiff rate. In that first span, batters had a 30.7 percent whiff rate on swings against deGrom’s slider. Since May 22, that rate is up to 39.4 percent.

He’s putting hitters away with the pitch more frequently, too. In his first nine starts, deGrom got a strikeout on 19.6 percent of his two-strike sliders. In his last 14 starts, that put-away rate is up to 27.6 percent.

The only pitchers with better ERAs since May 22 are Scherzer (1.17) and Ryu (1.53). But with both dealing with injuries, deGrom dwarfs them in innings pitched, with 91 in that span, to Ryu’s 76 and Scherzer’s 69. The Cy Young Award is not decided on the basis of compilation, but as deGrom and his slider continue to put forth strong outings while the other two NL contenders sit on the bench, at some point, deGrom’s case may be solid enough to take home the hardware yet again.