Cubs might face a sticky decision regarding their fifth starter

With Opening Day drawing ever nearer, key positional battles are coming into view. One decision David Ross will eventually have to make is picking a fifth starter. Marcus Stroman, Kyle Hendricks, and Wade Miley will likely man the top three slots, while Adbert Alzolay should take the fourth spot once he (fingers crossed) returns from the IL (keep in mind that’s likely to take some time).

Regardless, we already know Ross will need to settle on a fifth arm for the rotation. Here we examine four of the most likely candidates. Dark horses could emerge, so take these selections as a rough guess. Stats are for the 2021 season.

RHP Alec Mills, 119 IP, 5.07 ERA, 4.49 FIP

Why he might get the job: Mills has a high groundball rate on a team designed to smother grounders. He also can generate weak contact because of his ability to avoid barreled hits. His ERA last year was ghastly but the FIP was much less scary: it was within shouting distance of the 4.27 league-wide figure.

Why he might not: Mills’ pitches are unerringly attracted to bats; he just doesn’t get many strikeouts. Most of his Statcast metrics are Cubbie blue, which is not a good thing. A healthy Cubs infield could be one of the best defensive units in the majors, but if the bench gets pressed into service, more of those grounders will leak through.

LHP Drew Smyly, 126 2/3 IP, 4.48 ERA, 5.11 FIP

The arm so nice they signed him twice: Smyly returns to the Cubs after spending the 2018 season on their roster recovering from Tommy John surgery. The Cubs dealt him to Texas at the end of that season because … oh just read it, it’s complicated.

Why he might get the job: Smyly is sort of a mirror image of Alec Mills. He’s a lefty with good swing and miss stuff. He gives up a lot of flies, which seems to counter the Cubs’ current vision statement, but there will be times and places (including Wrigley when the wind is blowing in) where a flyball pitcher could be useful.

Why he might not: Screaming baseballs. Smyly gives up homers in quantity, as his swollen FIP attests. Last year he surrendered 27 dingers in just over 126 innings, or 1.9 HR/9, compared to a league average of 1.3. Most of his statcast ratings are poor, especially his spin rates.  And for now at least, the Cubs are severely short of lefty relievers. Aside from Smyly, only Daniel Norris and our next contestant are bullpen-available lefties on the current 40-man roster. (Brailyn Marquez could conceivably pitch his way into this mix, but he has yet to appear above A ball.)

LHP Justin Steele, 57 IP, 4.26 ERA, 5.51 FIP

Why he might get the job: Steele misses bats and gets grounders. He lights up the Statcast metrics; he is far and away the best of the four pitchers discussed here by those ratings. He is probably the most likely of these four to graduate to a mid-rotation role if he can harness his stuff. Which brings us to …

Why he might not: He gave up homers at a Smylyian (Smylyesque? Smylyacious?) rate last year, and while his pitches frequently miss bats, they also frequently miss the zone. Also, as discussed in the Smyly comment, the Cubs may want to stash him in their northpaw-heavy pen.

RHP Keegan Thompson, 58 IP, 3.38 ERA, 5.16 FIP

Why he might get the job: He has relatively high fastball and curve spin rates. Some of that gap between his ERA and FIP could be because he pitches effectively in front of the Cubs stout defense.

Why he might not: The rest of his metrics are mediocre. He’s something of a flyball pitcher and he struggled to locate his pitches at times last year. He’s the only one of these four rotation candidates with minor league options remaining, potentially making him more appealing as a flexible bullpen piece.

Cubs: Will foreign substance crackdown impact the team’s search for starters?

"If an umpire’s inspection reveals that the pitcher’s hand is unquestionably sticky or shows unmistakable signs of the presence of a foreign substance, the umpire will conclude that the pitcher was applying a foreign substance to the baseball for the purpose of gaining an unfair competitive advantage."

Yes, like a grisly hand clawing its way out of the grave, the sticky substances issue is back. As Tom Verducci reports in Sports Illustrated, MLB officials noticed rising spin rates toward the end of last season, suggesting that pitchers were finding ways around the league’s foreign substance enforcement efforts. The article details the enhanced surveillance and enforcement efforts MLB intends to carry out this season.

Three of our four rotation candidates were with the Cubs last season. They threw five pitch types each. The spin rates for 13 of those15 pitches increased between August and September. (Smyly, who pitched for the Braves last year, saw his curve spin rate increase, but the rates for his other two pitches declined.)

There is no way we can know whether these spin rate increases are related to the observations MLB has made, or whether they have anything to do with sticky substances. But for pitchers lurking at the margins of the rotation, the ability to pitch without foreign substances, or to pitch with them while effectively evading detection, could be a key tie-breaker if the race is tight.

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Ross may initially mix and match in the last two rotations spots. Piggyback starts and bullpen games are possible, especially if early season inclement weather adds yet more double headers to the already congested schedule. Injuries, an even more ominous threat this season than most, may force Ross’ hand. But if he has some freedom of choice, it will be interesting to see how he uses it. If I had to guess, I’d say he’ll stick with Mills in the fifth spot as long as he doesn’t implode early in the year, though my personal choice would probably be Steele. It will be a fascinating story line to follow.