Colin Rea Switched Lanes and Shook Up His Arsenal This Year—and He's Not Stopping Now

[Matthew Trueblood]

Image courtesy of © Kamil Krzaczynski-Imagn Images

In his last two seasons with the Brewers, Colin Rea was almost a fixture in the starting rotation all season. His improbable success—he entered 2023 having pitched just 20 innings in the majors over the previous six campaigns—kept an injury-riddled pitching staff humming. Milwaukee couldn't have won those division titles without him.

By the end of each year, though, the team quietly nudged Rea to long relief, and/or left him off their playoff roster. He didn't pitch in the postseason for them in either of their unceremonious first-round exits. The classic "get-you-there guy," Rea ran out of steam down the stretch in the process of helping his team get there. He's a selfless contributor, but once the league starts to adjust to him, he does sometimes struggle to counteradjust.

This year, he's hoping to change that. Rea started hot as the Cubs' fifth starter this spring. They won eight of the first 10 games in which he appeared, and six of his first seven starts. In mid-May, he owned a 2.38 ERA. Thereafter, though, he endured a six-start stretch in which opponents hit nine home runs and his ERA was 7.11. By the reckoning of most Cubs fans (who didn't watch closely, over the two preceding seasons, as he dealt with similar problems and made his next round of replies), he's slipped into the melange of options on which the team must keep trying to improve—another starter with underwhelming stuff who can't set the club up for success.

Quietly, though, Rea has averted outright disaster, and in fact, his last two outings have been terrific. Against the Astros in Houston and at home against the Cardinals, Rea combined for 11 2/3 innings pitched, giving up just three total runs on seven hits. He's still finding plenty of ways to get outs. To understand how, I think it's time we develop a comprehensive theory of Colin Rea.

First, we'd better establish the basics, because even those are changing all the time. Rea lived on a three-fastball mix with the Brewers; they like guys to mix all three looks for opposing batters. He used six pitches last year, and the balance of his arsenal was notable. This is what most kitchen-sink guys look like; hitters see four different pitches quite often.

This year, Rea is a very different kind of pitcher. He's added a seventh pitch, creating a true distinction between his cutter and a slider that he grips slightly differently and which has more depth. He's throwing a bit harder. The huge change, though, is the fastball mix. Instead of throwing the sinker and cutter just as much as the four-seamer, he's suddenly heavily featuring that four-seamer. In fact, everything else in his repertoire—the hard and the soft stuff—has taken a backseat to that true heater.

In a conversation inside the Cubs clubhouse at Target Field Wednesday Rea said the changes are partially the product of the team proposing changes, and partially his own sense that changing approaches made sense.

"A little bit of both," he confirmed. "I think over the past couple years, my four-seam has played pretty well. So coming in early, spring training and early in the season, it was an easy adjustment, but as you go along, the league kind of adjusts to you. So you’ve gotta make those in-season adjustments as well."

Rea said that when the Cubs signed him this winter, they made a presentation to him to show where he tends to have the most success within the zone. Once he embraced that study, the switch from a three-fastball hodgepodge to the four-seamer leading the way "just kind of happened," he said. With the team's help, he realized that the locations where his stuff thrives tend to be "four-seam dominant".

Meanwhile, he also moved across the rubber, from the third-base side to the first-base side. The Brewers almost universally nudge their hurlers toward the side of the rubber that creates a steeper horizontal angle for batters, and that did work for him, but once Rea moved on from the organization, he switched lanes.

"I just felt like on the third-base side, it gave the chance for the hitter to kind of see the ball a little bit earlier, whereas on the first-base side, I stay more closed, more direct toward home," Rea said. "Therefore, I can hide the ball a little bit longer. And I like to work to the glove side, anyway, so that just gave me a more direct path to that side."

While hitters might be fooled more by (for instance) a cutter-sweeper sequence toward the glove side of the plate if a pitcher releases the ball from way across the rubber, that movement pattern also introduces hurdles for the hurler. 

"Sometimes when you’re on the third-base side, you have to kind of clear your shoulder to get to that glove side, which can create some bad habits," Rea said.

Switching from the sinker-forward fastball trio to the four-seamer as the primary weapon makes that switch more viable. So does the slight mechanical change he's made this year, lowering his arm slot. As he mentioned, he's already on the right line to throw a glove-side four-seamer from his new location, whereas if he wanted to be filling up the arm-side sinker space, he'd need to be really making it run from this side to avoid leaving the pitch in the middle of the plate. Last year, with a higher arm angle, he would only have found trouble in trying to push the sinker to the arm side, so it worked much better to start there.

With the migration across the rubber and the lower slot, his four-seamer and sinker both run more to the arm side, and the sinker has room to do that without losing the plate. That mechanical change was only possible because he no longer had to force that front shoulder open, as he mentioned above.

Remember, too, that the Cubs talked to Rea about changing up some of the locations he emphasizes and how they play off each other. Changing position on the rubber affects that, too.

"On the third-base side, I threw a lot more backdoor cutters, backdoor sweepers, because that was the angle that I was at," Rea said. "On this side, I haven’t thrown as many, just because that’s a little bit harder a pitch to execute on that side."

Let's take a quick look at that in action. Here's a pitch Rea threw to Michael Busch, when the Brewers visited the Cubs last year. It's a sweeper, from his position toward the third-base side of the rubber.

That pitch still worked well, as you can see. But note the shape and location. It spends a lot of time over the white of the plate, and though it dips below the zone, it doesn't sweep to the glove side very much. Now, here's Rea throwing a sweeper to punch out Michael A. Taylor this year.

Both of those pitches are properly executed. You don't want a sweeper to a lefty to do what the one to Taylor did, or at least, you're less likely to risk throwing it that way. But that's the point. His change to a new mound position has informed a change in how Rea attacks hitters, because of what it's allowed him to do differently with his arm. You can really see that sweeper take off laterally this season, whereas last year's offering was a pitch that relies more on depth and can thrive on the arm side of the plate, if well-executed.

Ok, you say, but that example against Taylor is from back when Rea was great. We've already talked about how, since then, he's nosed steeply downward, then back up. What's going on there? As Rea alluded to, it's a matter of making adjustments within the season. Overall, yes, he's throwing far more four-seamers than sinkers or cutters this year—but now that hitters are hunting it, he's switched that back up.

"The last few times out, I’ve gone more three fastballs—four-seam, two-seam, cutter—with still my four-seam being the more dominant pitch, but mixing those in a little bit more," he said. "Teams, it seems like especially this year, they’re on the fastball from Pitch 1. So just a way to keep them off that pitch a little bit."

With the four-seamer leading the way, Rea can use his splitter and sweeper to chase swings and misses. However, at times, it makes more sense to take advantage of hitters who appear to have timed up the heat, by creating some wiggle they're not expecting.

"When you can see that they’re on time for the four-seam, they’re barreling it up, that’s a good time to go to the two-seam," Rea said. Getting early, weak contact can be just as valuable as working one's way to a strikeout, in multiple ways. First, inducing that kind of contact quickly means more efficiency within the outing, because one's pitch count stays lower and the opponent has to wait longer to get looks at the secondary stuff in one's arsenal. Second, sometimes, a misexecuted breaking or offspeed pitch to a hitter who's sitting on a heater in that zone can make them early in a good way—good for the hitter, that is.

As a pitcher, if the opposing batter is looking for a four-seamer, the surest way to disrupt them is to give them a version of that same pitch that attacks an unexpected part of the zone and has late movement they don't expect. Since Rea has used the four-seamer so much more heavily this year, he said, hitters sit on it and think less about the sinker and cutter. That makes it easier for him to get mishit balls with those altered flavors of the heat.

You just don't see pitchers fill up a movement plot this thoroughly very often. From the side of the mound on which (at least for now) he's more comfortable, Rea is using the four-seamer as the focal point, but he can move it a whole lot, vertically and horizontally—and he can do so throughout a fairly wide velocity band.

True kitchen-sink starters are rare, anymore. Throwing hard enough and having sharp enough command to succeed in the majors while maintaining four different glove-side pitch movement shapes and two to the arm side (plus the four-seamer itself) is excruciatingly hard. Rea has ridden a bit of a roller coaster of late, as he tries to harness that wide arsenal and make up for the fact that he doesn't have any one true out pitch. Because he's exceptionally open-minded and has the gift of manipulating the ball this way, however, he's already felt his way through a tough stretch and back to a good place.

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