It's "best tools" week! For the third straight year, Keith Law lays out his rankings (and reasoning) for the players with the best tools in baseball. Tuesday he evaluates the top pitches across six different pitch types (see last year's rankings here). Monday he ranked the best hitting tools; Wednesday will be the top fielding/throwing tools.

Best fastball

1. Chris Sale, Boston Red Sox

2. Aroldis Chapman, New York Yankees

3. James Paxton, Seattle Mariners

4. Joe Kelly, Boston Red Sox

5. Justin Verlander, Detroit Tigers

Of course, the hardest throwers are all relievers -- FanGraphs' velocity data shows the top 12 pitchers, by average fastball velocity, work out of the pen, with Cincinnati's Luis Castillo the hardest-throwing starter at 97.5 mph -- so this list ends up a mashup of the relievers with the biggest velo and the starters with the most effective fastballs.

Sale takes over the top spot here as he has taken everything to a new level this year, his first in Boston, with the most effective fastball in baseball this year (by FanGraphs' pitch values, estimating value added/cost by each pitch based on game results). Sale is currently posting career-best strikeout and walk rates, and he's doing it with all three of his pitches -- but his fastball has been the most valuable, preventing 27.6 runs above average this year according to FanGraphs.

Chapman is the hardest thrower in MLB history, but this year his fastball has been less effective, in part because his secondary stuff isn't as good and hitters are able to cheat a little more to get to his heater. Chapman also has the known habit of relying too much on his fastball when there are men on base, giving hitters even more of an advantage against him. His velocity is still there, and fixing him might be as simple as getting him to throw a few more sliders each outing so that hitters aren't overconfident that they're going to see a fastball.

Best curveball

1. Corey Kluber, Cleveland Indians

2. Lance McCullers Jr., Houston Astros

3. Aaron Nola, Philadelphia Phillies

4. David Robertson, New York Yankees

5. Clayton Kershaw, Los Angeles Dodgers

Kluber's curveball is the current gold standard. By FanGraphs' pitch values, it has been the most valuable curveball in baseball in 2017 and in 2016, second in 2015, and first in 2014. Part of why it's so effective is that it's harder than a typical curveball, more of a power slurve than a classic curveball, with the velocity of a slider but the depth of break of a curve. It's also effective because Kluber commands the heck out of it.

McCullers also throws a power curveball at slider velocity, far and away his most effective pitch, although he's back on the disabled list now with a back injury. Nola's 2017 breakout has been more about the revised grip on his changeup, giving him a potent third pitch, but his curveball remains his primary out pitch.

Best slider

1. Max Scherzer, Washington Nationals

2. Clayton Kershaw, Los Angeles Dodgers

3. Chris Archer, Tampa Bay Rays

4. Andrew Miller, Cleveland Indians

5. Greg Holland, Colorado Rockies

I feel like we're living in a golden era of sliders right now as any of those top four guys would end up in a discussion of the best sliders in MLB history. You also could reorder those guys however you liked and I wouldn't put up much of a fight.

Scherzer's has been, statistically, the most effective, but my subjective opinion would probably put Kershaw's first if I hadn't looked at the values of those pitches. Miller is behind the three starters for me because he depends more on throwing the slider off the plate, which was one of the reasons he didn't work out in the rotation -- if hitters could pick up the slider, they could lay off it, betting it would end up out of the zone.

Others I considered include Sale, Jhoulys Chacin, and, when healthy, Madison Bumgarner.

Best changeup

1. Danny Salazar, Cleveland Indians

2. Chris Sale, Boston Red Sox

3. Alex Wood, Los Angeles Dodgers

4. Chris Devenski, Houston Astros

5. Edinson Volquez, Miami Marlins

Salazar is the default choice for me here -- when he's healthy, that pitch is devastating, a changeup with split-like action that has been the most valuable change in MLB since the start of 2015.

Sale has always had a plus changeup, even as an amateur, and while his other stuff has improved since then the change remains a critical weapon for him, especially since right-handers get a long look at the ball from his low arm slot.

Wood's breakout this season is more about health than stuff, although he has been falling to earth lately too as his velocity returns to normal (for him) levels, but the changeup again is the constant, a pitch he has had at least since college and still his most valuable offering.

Volquez seems like he should have pitched himself out of baseball long ago, with two atrocious seasons in his past four, but he has kept going and the plus changeup is the main reason why. Unfortunately underwent Tommy John surgery earlier this month.

Best splitter

1. Masahiro Tanaka, New York Yankees

2. Hector Neris, Philadelphia Phillies

3. Matt Shoemaker, Los Angeles Angels

4. Jeff Samardzija, San Francisco Giants

5. Blake Parker, Los Angeles Angels

Tanaka has had his ups and downs but the splitter remains his best pitch, an offering that is still more commonly taught in Asian baseball markets than it is here.

Neris came a bit out of nowhere to succeed Ken Giles as the Phillies' closer thanks largely to his splitter, which accounts for nearly half of the pitches he throws and, after a little trouble earlier this year, has returned to form as one of the best splitters in the majors.

Shoemaker, who went from unknown prospect to big league starter almost overnight and produced 5 WAR over three full years in the Angels' rotation, had surgery to repair a nerve in his right arm and is out for the season -- and you will certainly find people around the game who believe throwing the splitter leads to elbow issues. (I'd call it anecdotal. I've seen no real evidence to indicate this is true or to exonerate the pitch.)

Parker came into this year with just 90 major league innings and a 3.87 ERA, but his breakout campaign, with a career-best 52 2/3 innings and 2.39 ERA this season, has come thanks to his fastball/splitter combination, which account for more than 90 percent of his pitches thrown, with the plus splitter helping keep hitters off his above-average fastball.

Best cutter

1. Kenley Jansen, Los Angeles Dodgers

2. Bryan Shaw, Cleveland Indians

3. Jon Lester, Chicago Cubs

4. Mike Leake, St. Louis Cardinals

5. Corey Kluber, Cleveland Indians

Jansen is the new Rivera. Where Mariano was the default choice for the top cutter for almost two decades, Jansen is now the king, with the most valuable cutter in baseball over the 2015-17 period.

Shaw's cutter isn't that far behind, coming in very hot with fastball velocity but slider break. Lester has obviously built his entire career on the cutter, and it's the one pitch that's still working for him in an otherwise disappointing year. Leake was always more of a two-seam guy than a cutter artist, but his cutter has been shorter this year with less downward break, making it harder for hitters to distinguish it from his fastball. Kluber's cutter gives him an in-between pitch to fit below his fastball and above that power slurve, so he has a full range of velocities across a continuum three pitches, a style and repertoire that Andy Pettitte used for much of his 18-year career.