Just because the 2020 season hasn't started yet doesn't mean baseball fans have to forget what it's like to watch the best of the best. This week, MLB.com is highlighting some of the nastiest pitches in baseball -- a different pitch type every day, with five pitchers featured for each (no repeats), picked by our reporters. Check out the nastiest fastballs, the nastiest curveballs, the nastiest sliders and the nastiest changeups here.

Last up: baseball's nastiest unique pitches.

A lot of the coolest pitches in baseball don't fall into the traditional categories.

If you're on a quest to find the nastiest pitches in the game, you're going to have to go beyond the normal fastballs, curveballs, sliders and changeups, and look for the pitchers who have gone off the beaten path and developed their own signature offerings.

Here are five of baseball's most personalized nasty pitches.

Zack Greinke's eephus curve
Why he's so nasty: 29 strikeouts on pitches slower than 70 mph

Greinke's eephus curve is everything baseball should be. A Major League pitcher has no business even daring to throw something like this -- a curveball that lollipops in at well under 70 mph … sometimes even under 60 mph. And a pitch like that surely has no business being so ridiculously unhittable. But that's one of the many, many, many great things about Zack Greinke. Normal rules don't apply when he pitches.

Greinke threw 214 curveballs slower than 70 mph last season, by far the most of anybody. Facing those slow curves, hitters went 6-for-77 ... an .078 batting average. Greinke got 42 swings and misses on sub-70 mph pitches, more than double the next-closest pitcher (Jason Vargas, 17). He struck out 29 batters, 12 more than anyone else (Ryne Harper). His slowest strikeout pitch of the year? 59.3 mph. Incredible. Greinke's eephus curve is a joy to behold.

-- David Adler

Kirby Yates’ splitter
Why he's so nasty: +4.0 inches of drop vs. MLB avg.

This pitch quickly catapulted Yates from a fairly anonymous reliever bouncing around the fringes of Major League rosters all the way to one of the game’s top closers. The change happened in April 2017, when Yates was claimed off waivers for the second time in six months, this time by the Padres. They encouraged Yates to embrace the splitter, and off he went.

Only Tyler Clippard gets more vertical movement on his splitter than Yates, compared to the MLB average while factoring in velocity. The pitch is there, and then it simply falls off the table, leaving hitters to either miss entirely or pound the ball harmlessly into the ground. Over the past two seasons, opponents have missed on 39% of their swings against Yates’ splitter, and even when they have made contact, it’s been hit on the ground 63% of the time. The result? A .158 average, .202 slugging percentage and 106 strikeouts in 243 plate appearances ending with the split.

-- Andrew Simon

Aníbal Sánchez's butterfly changeup
Why he's so nasty: 19.5 mph differential between changeup and four-seamer

When you see Sánchez's changeup, it's easy to understand why it's known as the "butterfly." Sánchez throws the pitch around 71 mph on average, and it seems to float toward the plate like a winged creature before gravity finally sets in.

Sánchez doesn't use his changeup often, keeping it in his back pocket and breaking it out when batters least expect it. The strategy has worked to his advantage, as he has limited opponents to a .087 average (8-for-92) with 51 strikeouts on changeups over the past two seasons.

"[It] makes everybody go crazy," Nationals right-hander Max Scherzer said of his teammate's changeup. "Every time we see it we love having fun with it. We've all tried to throw the butterfly changeup. No one can ever throw it the way [Sánchez] can."

-- Thomas Harrigan

Joey Lucchesi’s "churve"
Why he's so nasty: 34.6% usage, 40.3% whiff rate since 2018

Sometimes it’s Barry Zito’s tumbling slow curve. Sometimes it’s Randy Johnson’s sweeping slider. Sometimes it’s Cole Hamels’ fading changeup. Lucchesi’s homemade churve can be all of those things, while also being unlike anything else in the Majors right now. The speed isn’t quite right. It doesn’t move the way it’s supposed to. It’s a beautiful "ugly duckling." All the movement -- and there’s a ton of vertical movement, more than any other big league changeup -- happens behind the scenes, making you wonder how hitters keep missing something so appetizing. It’s kind of like watching someone failing to catch a feather in the wind.

Perhaps Lucchesi’s churve is a gimmick pitch, successful only because hitters haven’t seen it before -- and therefore doomed once they’re familiar. But that was the thought after Lucchesi’s 2018 rookie season, and his churve performed even better in '19. Over the past two years, only two starters have thrown more "changeups" than Lucchesi, and yet his churve still tied for the fourth-highest changeup whiff rate, behind Luis Castillo, Stephen Strasburg and Cole Hamels. Gimmick or not, Lucchesi has ridden his creation from tiny Southeast Missouri State to a Major League starting rotation. I'm rooting for this flying-saucer pitch to stay in my life for a while longer.

-- Matt Kelly

Yonny Chirinos’ splitter
Why he's so nasty: 42.1% whiff rate

Chirinos relies on a two-seamer/splitter/slider combo, ranging from 93.9 mph on the two-seam to 85.9 mph on his split and 87.5 on his slider. Within that mix, his splitter was his best strikeout pitch in 2019 -- with a 22.7% putaway rate, his highest of any pitch type. He got his best results on that pitch, too -- with a .133 batting average allowed that was second-lowest among regular offspeed users (that includes changeups and splitters), and a .212 slugging percentage that was fourth-lowest.

Chirinos generates a lot of swings and misses on the pitch. He had a 42.1 percent whiff rate on swings against his splitter, well above the Major League average of 35.3 percent on that pitch type.

He served as a traditional starter for the Rays -- something worth distinguishing, given the team’s frequent use of the opener -- for much of last year before missing time with injury and coming back in a shortened role at the end of the season. Keep an eye out for that splitter moving forward.

-- Sarah Langs