Entering Tuesday’s game, the Diamondbacks bullpen ranked 27th in ERA — and yet, one of baseball’s most dominant relievers to date is on their team. After seven seasons in the minors and four fragmented MLB stints from 2016 to 2021, Joe Mantiply — at age 31 — is hitting his stride.

In 20 appearances in 2022, the lefty has a 0.51 ERA, 0.85 WHIP and 15 strikeouts against just one walk. Opposing hitters are batting .212/.224/.212 against him, and he hasn’t allowed an extra-base hit all season.

Mantiply, like most D-backs relievers, isn’t overpowering. Having all but abandoned his four-seam fastball, he now relies primarily on a low-90s sinker, a changeup and a slider.

What’s most impressive is that he has been equally effective against both righties and lefties — a skill that’s more important than ever under MLB’s three-batter minimum rule that was introduced in 2020.

Entering Tuesday’s game, righties were slashing just .179/.200/.179 against Mantiply, compared to a .318/.368/.518 batting line last season.

Lefties are also faring worse against him this year, with a .250/.250/.250 batting line compared to .261/.346/.362 last year.

It’s apparent that manager Torey Lovullo feels comfortable using him in any situation. Mantiply has faced significantly more righties (41) than lefties (26) this season. The lefty knows he can be effective no matter what type of hitter is at the plate.

“My changeup works really well to righties and my slider works really to lefties, so I’m able to kind of attack both those types of hitters differently,” Mantiply said in a guest appearance on Monday’s episode of the PHNX Diamondbacks Podcast.

His approach is not complicated. In general, Mantiply throws changeups down and away to righties and sliders down and away to lefties. Let’s hone in on the latter for a moment.

Mantiply’s slider was arguably his most effective pitch last year, and it’s been very good to start 2022. Here, Mantiply dots the glove and gets Freddie Freeman to go down swinging.

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Mantiply’s ground-ball rate on the pitch has jumped from 26.9 percent last year to 46.2 percent so far in 2022. Granted, that’s a sample of just 13 batted balls so far, but it’s an encouraging start.

Here, Mantiply gets Dominic Smith to roll over the top. You’ll notice the pitch is in almost the exact same location as the slider to Freeman: down and away.

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As Mantiply outlined above, his primary weapon against righties is his changeup, and that pitch has been more effective than ever in 2022.

For starters, he’s doing a better job keeping it down in the zone. Of the 70 changeups that Mantiply has thrown this season, 56 of them (80 percent) have been at or below the lower third of the strike zone. That’s up from 72 percent last year.

That, combined with two additional inches of vertical break compared to last year, has led to a ground-ball rate of 57.9 percent on the pitch, which is up from 48.4 percent last year.

This well-placed changeup gets Alex Bregman to bang the ball into the ground.

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Although the whiff rate on Mantiply’s changeup is down slightly in 2022, the pitch is more than capable of inducing swinging strikes. Here, Seiya Suzuki swinging right through it. Again, notice the location? It’s down and … okay, I’ll stop.

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Like his changeup and slider, the ground-ball rate on Mantiply’s sinker has also seen a dramatic increase, from 55 percent last year to 73.3 percent this season. Opposing hitters are 4-for-17 when they put the pitch in play. Again, all four of those hits are singles.

Bringing this all together, Mantiply’s ground-ball rate has increased significantly overall — from slightly above-average in past years to elite so far in 2022. That, combined with a slight bump in overall strikeout rate and even more pinpoint command than we’ve seen in the past, has elevated Mantiply to a level that he’s never reached before.

Consider also that Mantiply is tied for the league-lead in relief appearances with 21, and it’s hard to ask for more. In a Diamondbacks bullpen that has floundered through the first quarter of the season, Mantiply’s role only figures to expand from here.

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Top photo: Rick Scuteri/USA TODAY Sports