Just how good are Rick Porcello and Kyle Hendricks?

I have this theory: Most pitchers who have the ability to reach the major leagues have the potential to become good major league pitchers.

Consider this 21-year-old rookie: 6-14, 5.61 ERA, 155 2/3 IP, 181 H, 17 HR, 74 BB, 101 SO.

Would you have bought stock in those numbers? This kid was obviously young, so maybe he was rushed to the majors, but he got beat up pretty good. That kid was Greg Maddux, and the next year he won 18 games.

How about this 25-year-old left-hander: 6-10, 5.15 ERA, 153 2/3 IP, 184 H, 20 HR, 52 BB, 123 SO.

This pitcher didn’t throw hard, and this was his second season in the majors. He looked like a fringe major leaguer. Two seasons later, Dallas Keuchel won a Cy Young Award.

We could play this game all day. There is so much that goes into succeeding as a major league pitcher that predicting breakouts or consistent excellence is challenging. Primary, of course, is health. Stuff is important, but when we say “stuff,” we usually think of velocity. Yes, hitting a 98 mph fastball is hard. Well, hitting a 90 mph fastball is difficult, as well -- go to your local batting cage and turn the pitching machine up to maximum and see how often you make contact. So stuff can mean velocity and movement.

Then factor in everything else: command, smarts, deception, a new pitch, changing your arm angle, changing your grip on an existing pitch, adjusting where you stand on the rubber, gaining more confidence, the defense behind the pitcher, a new ballpark, a pitching coach who gives the exact advice needed and you never know who might become the next Rick Porcello or Kyle Hendricks.

Those were the big surprises last year. Are they for real? Through his first seven seasons, Porcello proved himself as a mid-rotation innings cruncher with a 4.39 ERA. In 2016, the Boston Red Sox right-hander started throwing his sinker more often, went 22-4 with a 3.15 ERA and career-high 223 innings and won the Cy Young Award.

Hendricks spent his first full season with the Chicago Cubs in 2015 as a nondescript right-hander, a guy with a below-average fastball and 3.95 ERA. In 2016, he started throwing his sinker and changeup more often and his fastball less often and went 16-8, led the NL with a 2.13 ERA and finished third in the Cy Young voting.

It will be interesting to see if they can find their 2016 form -- or at least their 2016 results. Porcello has a 5.32 ERA through four starts and has allowed a .298 average and five home runs. Hendricks has a 6.19 ERA through three outings and has walked seven batters in 16 innings and allowed four home runs.

For Porcello, it’s possible that his great 2016 was simply a product of BABIP and that he has been a little unlucky so far in 2017:

Aside from what happened when batters put balls in play, Porcello did improve his strikeout and walk rates, so there was something going on in 2016 besides good luck and good defense behind him. What’s interesting about his numbers is that, while he threw his sinker more, the improvement seemed to arrive not so much from his sinker being a dominant pitch, but the sinker making his other pitches -- especially his regular fastball -- more effective.


Sinker: .302/.344/.489

Fastball: .175/.213/.314

This season, batters are hitting .357 against Porcello’s sinker and .261 against the fastball. But here’s something to watch: Batters are swinging more often against the sinker, 53 percent of the time versus 43 percent in 2016. If the sinker isn’t a dominant pitch by itself, then it makes sense for batters to be more aggressive against it. This is perhaps an adjustment they’re making.

Anyway, Porcello certainly has had some bad luck, as batters are hitting .417 on ground balls against him compared to .217 in 2016. The MLB average is .237 on grounders. That .417 number will come down. Will Porcello be as good as 2016? It’s boring to predict regression because you can say that for any pitcher who had a great season, but Porcello likely will regress. I do, however, like him to post a sub-4.00 ERA, maybe in the 3.50-3.75 range.

Hendricks' 2016 season was built on hitting corners and inducing soft contact. ESPN Stats & Information tracks "well-hit average," or the percentage of hard contact given up. Hendricks had a .089 well-hit average in 2016, best in the majors; in 2017, he’s at .290.

So his early struggles are more clear. In particular, lefties are hitting .267/.371/.600 against him, and batters are slugging .636 against the cutter/sinker (different systems label the pitch differently). They hit .164 and slugged .299 against it last year.

The cutter was arguably the key to his big season, allowing him to throw fewer of his 87 mph fastballs and giving him another effective pitch against lefties. Note that his fastball velocity is down 2.4 mph (even though the tracking methodology has changed this year and fastballs are averaging about 0.5 mph faster as a result).

It's early and all that, but Hendricks’ drop in velocity is a red flag. The ineffectiveness of the cutter/sinker is a red flag. Part of the equation of being a great pitcher is doing it year after year, with your body being able to handle 200-plus innings without any decline in stuff. Maddux was able to do it every year. Keuchel followed up his Cy Young season with a poor 2016 (although has looked good early in 2017).

Which pattern will Porcello and Hendricks follow?