Can the Cubs Piggyback Their Way to Glory?

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Edward Cabrera fired five no-hit innings for Double-A Knoxville Wednesday, and is no more than a fortnight from returning to the Cubs rotation. It's more likely that he comes back after just one more rehab appearance—and possible, even, that his next outing marks his return to the active big-league roster. He only threw 64 pitches against those minor-league batters Wednesday, but it might not take much more than that to fulfill his responsibilities each time through the rotation for the Cubs down the stretch.

Thanks to the aggressiveness of the front office in late June and at the trade deadline, Chicago has found its way back to the place of exceptional starting pitching depth in which they felt they stood to begin the season. Your mileage may vary, but my own depth chart for healthy (or nearly healthy) starters for the team right now reads:

They started the season with a corps equally deep, but including several different names. Gausman, Holmes and Peterson were not yet in the organization. Cade Horton, Ben Brown and Jameson Taillon were in the mix instead, with the team holding out hope that they would also get starting contributions from Justin Steele. Six weeks ago or so, however, the team was down to Boyd, Imanaga, Rea and Assad, with Horton, Taillon, Brown and Cabrera all on the injured list. Piece by piece, returns from injury and trades have taken them from having to give Jordan Wicks a last chance to hack it in the bigs to once again feeling that their rotation overflows with talented arms, even though Taillon is now gone and Brown and Steele look likely only to pitch in relief (if at all).

We saw how Craig Counsell will address this superabundance of starters over the course of his first week with all the new guys stepping into their roles. After four innings from Holmes in his Cubs debut Saturday, Counsell turned to Rea for the other four frames of a loss in Kansas City. On Wednesday night, Peterson went five innings, and Assad pitched the final four. Even without Cabrera back in the frame, Assad and Rea have been moved to the bullpen, but they're not switching to leveraged short relief. Rather, they're becoming long relievers—and, in some sense, that makes them piggyback starters.

In the short run, of course, Counsell will still try to get length from the likes of Gausman, Boyd and Imanaga. Only Holmes, Peterson and Cabrera will be removed proactively, rather than based on their performance and the game context. But it's easy to see where this is going. As Chicago tries to catch the Brewers and win the NL Central—and, whether they succeed in that chase or not, as they prepare for the postseason—they're trending toward a piggyback rotation. Let's talk about why and how that works.

Firstly, of course, a caveat: there's no guarantee whatsoever that the team will stay healthy enough to carry out a piggyback plan for their starters. As any fan who has followed the team all season knows perfectly well, eight pitchers can become four in a hurry. It's more likely to be five or six. What's fairly unlikely is that, over the final quarter of the regular season and when October comes, the Cubs really will have eight starting-capable pitchers to whom Counsell wants to turn for multiple innings in each outing.

Let's assume, though, that they spend at least some time with all eight pitchers available to them. That could be the situation as soon as early next week. In such a case, there are three main reasons to deploy starters in tandems, as piggyback partners:

Gaining matchup advantages. This one is obvious. If you use tandem starters of opposite handedness or who use very different arm angles, pitch shapes or release points, you can force opponents to choose between making early changes to their lineup (locking them in and making them more prone to matchup play at the end of the game) or losing an edge in the middle innings.
Thwarting familiarity. Every modern manager is aware of the times-through-the-order penalty, but they have to weigh their desire to deny batters a third look at the starter against their need to keep the bullpen fresh. Piggyback starters make that less of a concern. Counsell, for instance, can take out one half of a starting tandem after 15 or 16 batters, as soon as the right matchup opportunity presents itself. Having a plan to use the second half of the tandem for the next 15 or 16 batters should get him close to the end of the game. Using a starter an opponent won't see again in a series as a major part of the relief solution for a game also means denying batters a look at one or more short-relief arms you'll deploy later. They not only don't see any hurler three times, but don't see a reliever twice in three or four days.
Limiting and managing workloads. Holmes, for instance, is still working his way back to full strength after three months on the shelf with a broken leg. Cabrera is in a similar situation. Rea tends to wear down at the ends of seasons, despite his big frame and deep arsenal. Getting maximal value from certain pitchers means preventing them from piling up too many innings and being exposed to either injury or exhaustion.

Right now, the Cubs are unlikely to use Rea, Assad, Peterson or Cabrera (the latter of whom would seem to be rivals for the final spot in the starting rotation if and when all eight arms are active again) as piggybacks for Boyd, Imanaga or Gausman. Those three starters need to soak up innings as Chicago tries to keep everyone fresh, at least until their bullpen gets healthier and rosters expand to allow a 14th active pitcher come September. How best to deploy a piggyback plan depends on your needs at any given time.

When September comes, however, and especially in the playoffs, all eight of these guys will be candidates for some kind of tandem plan. Picking the right pairings is vital. So, how should the team do it? Which pitchers fit best together in what would be a fairly noval usage plan for a team trying to make a deep run into October?

Boyd & Cabrera: Timing Nightmares
In a perfect world, you'd always have one righty and one lefty in a tandem like this. Boyd and Cabrera check that box. They also offer another layer of difficulty, though. Boyd is no true soft-tosser; he can touch 95 MPH with his fastball. But he's elite at producing mistimed swings, because he leans so heavily on a changeup and breaking balls that feature big velocity differentials from even his more typical, low-90s heater. Cabrera, by contrast, throws exceptionally hard, and even his changeup relies more on movement than on velocity gap. He's power all the way. Boyd will leave you off-balance, and often early. Cabrera will look like he's throwing 105, compared to the southpaw. That's all exacerbated, for a batter, by the fact that each hurler throws from a relatively low slot, so there's about 5 feet of horizontal difference in their release points.

Imanaga & Rea: Forcing Splits
Again, one lefty and one righty. This time, there's no huge difference in velocity or timing tendencies, but the differences in style and delivery are enormous. One way two pitchers can frustrate hitters' timing in successive at-bats even if their raw velocities don't differ much is by having big differences in their extension at release. Hitters don't time their swings purely to numbers on the radar gun. They see a hurler's delivery and respond to it. A fastball that plays slightly faster than its unadjusted velocity because of plus extension can prime a hitter differently than one that plays down, and if the next pitcher they see has the opposite relationship between their velo and their extension, the effect is magnified. Imanaga, with his drop-and-drive delivery and short stature, has below-average extension; Rea is above average. Statcast sees a difference between their average arm angles, but hitters see an even bigger one, because of the ways their bodies actually move. Rea would also benefit tremendously from coming in to replace Imanaga, who is likely to prompt opponents to load their lineup with right-handed batters.

Gausman & Holmes: Shapes and Angles
With Imanaga and Rea, we talked about how tandem starters with different relationships between actual and perceived velocity can pose problems for batters, especially if their deliveries are extremely different from one another. What about two starters who look strikingly alike to batters, and who even pitch with the same hand, but whose pitch shapes are radically different from one another?

Gausman and Holmes have very similar arm slots, just above the average three-quarters slot. Holmes works from the first-base side of the rubber; Gausman works from the middle. Their deliveries are similar enough to invite a hitter to see them the same way. However, Gausman gets much more extension toward the plate than Holmes does. He uses a high-rise fastball and a great splitter, but doesn't get much value from moving anything toward the glove side. Holmes has one of the heaviest sinkers in the sport, but everything else in his arsenal moves to the glove side. They're two pitchers whom hitters will want to see as similar, but whose stuff could not move more disparately.

Peterson & Assad: Grounder Guys
We're back to basics here. Peterson is a lefty; Assad is a righty. Peterson has elite release extension; Assad's is merely average. Peterson throws from a standard slot at 6-foor-6; Assad is a shorter, stockier guy who throws from a much higher angle. Neither is a guy you want opponents to see three times in a game, and neither will miss many bats, but they can both keep the ball on the ground and induce weak contact. That gets even easier if an opposing lineup has to hedge against playing matchups on Peterson because Assad is lurking, or if they don't hedge and Assad thus comes in to face a lineup chock-full of right-handed batters.

Though Gausman, Boyd, Imanaga, Cabrera and Holmes have each looked like legitimate front-line starters in playoff series at some point in their careers, none enter the stretch run of 2026 as that kind of pitcher. The Cubs did add to their bullpen at the deadline, too, and they'll get some important reinforcement in the days ahead for that unit, but they still don't have an elite 'A' bullpen for a playoff club. Their best bet, for the final stretch of the regular season in which they'll try to secure a bye and keep people fresh at the same time and when the postseason begins, is not to treat any of their starters as traditional aces and hand the game over to multiple one-inning relievers. It's to piggyback their bevy of strong starters and shorten games in a new way. As they've already shown, they're thinking along these lines, too. It will be fascinating to see how often they piggyback their way to wins (or even use the strategy to cushion the blow of losses) in the weeks ahead.