Cubs Have Major Decision To Make Regarding Ace Starter Marcus Stroman

The Chicago Cubs face quite the conundrum in dealing with their ace starting pitcher, Marcus Stroman. On one hand, he’s in the midst of arguably his best season, both quality and quantity-wise, as the Cubs are in the thick of the NL Central race despite a sub-.500 record. On the other hand, he is already paid well at $25 million per season, and is sure to be looking for a raise this winter. What’s a team to do?

First, the club needs to get a handle on Stroman’s true talent level. While leading the NL in wins, ERA, starts, complete games, shutouts, ERA+ and WHIP are all impressive, they only tell you so much. What they do shout clearly is that Stroman, unlike many veteran pitchers, has handled the pitch clock with great aplomb. His quantity numbers are beyond reproach.

But as we know, wins and ERA can be very misleading, especially in two-and-a-half-month sample size bits. We need to bring things down to the micro level and analyze Stroman’s season on a batted ball and pitch-by-pitch level.

First and foremost, Stroman is one of the game’s premier grounder generators. Through Sunday’s games, his 60.5% grounder rate and 2.1 degree average launch angle allowed are on the better than anyone not named Framber Valdez plane among ERA qualifiers. Those two numbers are in character with the rest of Stroman’s career and better than any of his full season marks since 2018.

While he has always induced a significant number of grounders, he hasn’t thwarted their authority all that effectively. His average grounder exit speed allowed of 87.3 mph is over a full standard deviation higher than league average. Both his overall (89.9 mph) and liner (95.5 mph) average exit speeds allowed are also over a full standard deviation worse than league average as well.

All of those grounders carry the day, however, and make him an above average contact manager. His 2023 Adjusted Contact Score of 86 is right in line with career norms and ranks second among his seasonal numbers (79 in 2019). One big caveat here, however – his UNADJUSTED Contact Score thus far in 2023, i.e., based on his actual numbers, is an amazing and quite fortunate 50. MLB hitters are batting .659 AVG-.847 SLG on liners this season; they’re hitting .525 AVG-.610 SLG against Stroman despite hitting the ball much harder than average.

We also need to look at his K/BB profile to get a better feel for his 2023 performance. His 21.6% K rate ties his seasonal high mark set in 2021, while his 9.1% BB rate is his highest ever. Both marks sits squarely in the league average range. This means that Stroman is only going to be as good quality-wise as his contact management performance – his K/BB profile isn’t going to slide him higher or lower. That 86 Adjusted Contact Score keys his 86 “Tru” ERA-, which is higher than both his ERA- of 57 and FIP- of 80.

So far, I’ve got Stroman as an above average pitcher but not a true ace. Let’s take a look at his arsenal on a pitch-by-pitch basis to see there is any basis for additional upside.

Each season, I grade out every qualifying pitch for every starter with 135 or more innings based on their bat-missing and contact management performance compared to league average. Last season, four of his pitches qualified – his cutter and sinker got “B+” grades, his slider got a “C+” and his splitter got a “D+”.

In 2023, the good news is that he’s throwing splitter less and it no longer qualifies to get a letter grade. The bad news is that all three of his qualifying pitches check in as league average offerings, earning “B” grades.

He throws his sinker the most, with a league average range 5.1% whiff rate and slightly better than league average 85 Adjusted Contact Score. Next comes his slider, which also has a slightly better than league average 85 Adjusted Contact Score, paired with a slightly below league average 13.5% whiff rate. Next comes his cutter, with a well above average 14.4% whiff rate and slightly below league average 118 Adjusted Contact Score. All viable offerings, perhaps with “B+” upside, but no go-to plus pitches.

So what would I do if I was calling the shots for the Cubs? I’d try to compete with him fronting my staff leading up to the deadline, and continue to exchange extension numbers with his representation. Based on the standings leading up to July 31, he might be a very attractive rental trade target should the Cubs deem themselves a non-contender at that time. I simply cannot see bestowing a 5+-year, $30 million per season contract upon him, however. He is a good pitcher who in a given year can be an elite contact manager, but elite contact managers with average K/BB profiles are not elite starters. He simply isn’t anything near the dominator his mainstream numbers currently suggest.

There will be a club willing to give Stroman the years and dollars he’ll be looking for this offseason, but it appears he’ll be negotiating off of a platform season that simply doesn’t reflect his actual worth. He’s a really fun pitcher to watch – durable 5’7” righties who hammer the ball down in the zone don’t come down the pike very often – but he’s not an inner-circle foundational piece that can be counted upon to carry a staff over the next half-decade.