Seiya Suzuki's Timeline is Relatively Clear, Once You Remove the Bad Data

[Matthew Trueblood]

Image courtesy of © Sam Navarro-Imagn Images

Seiya Suzuki suffered a sprain of the posterior cruciate ligament in his right knee, the Cubs announced this week. It's not great news, in that Suzuki has a tangible injury that will require recovery and a slight reset of his preparation for the regular season, but the diagnosis could be far worse. A sprained PCL is usually a fairly minor injury in a baseball player; the severe form of the injury usually involves a traumatic collision, like an awkward tackle on the football field. Kyle Schwarber tore both his ACL and his PCL in 2016, as fans might remember, but that was because he and Dexter Fowler collided so brutally in the outfield at Chase Field in Arizona. Suzuki suffered no such incident, and his sprain is considered mild.

Before delving deeper into the prognosis for a player dealing with a PCL sprain, we should pause to make a clarification, because the Cubs ended up having to do the same on Tuesday. Initially, Suzuki's injury was reported as a strain of the PCL, which left anyone with substantial familiarity with sports medicine a bit confused. Sprains and strains are similar, but they're different. A strain is a stretching or tearing of either muscles or tendons—the latter being, as you might remember from high-school biology, the tissues that connect bones to muscles. Sprains, by contrast, are exclusive to ligaments, which connect bones to other bones and are the most important tissues in stabilizing joints.

Because of their respective jobs, ligaments are a bit more likely to be stretched (and thus sprained) than tendons are to be strained. Any sudden roll or twist of your shoulder, ankle, elbow, wrist or knee is liable to produce a mild sprain of a ligament, and those can cause discomfort, lost range of motion, or weakness in the joint. Because they exist to absorb those stresses and keep joints functioning, though, ligaments handle mild sprains well, and recovery can be quick.

By contrast, a strain of a tendon usually signifies a somewhat less natural or frequent movement. They're more likely to be overuse injuries. Muscle strains, of course, range from micro-tearing that merely allows our tissues to grow and strengthen to full ruptures, but they reflect the pushing of that muscle to a point of failure, whether through repetitive stress or an especially acute exertion of an unready tissue.

No sports fans have been led into a deeper forest of confusion about these related injury types more than baseball lovers, because of the nature of elbow injuries in pitchers. The most infamous elbow injury is the torn ulnar collateral ligament, which you might think would begin as a sprain. Sometimes, it does. However, diagnoses of elbow sprains are relatively rare, compared to diagnoses of strains of the flexor tendon in the forearm or the muscles of the forearm or the biceps. Often, before a pitcher's UCL gives way, they're diagnosed with a strain, so when the UCL then tears and they undergo Tommy John surgery, 'strain' is still in the air around them. Fans attach that term to the injury that sent them to the surgeon's slab.

In reality, because the combined forces applied to the arm throughout the pitching motion are so violent, most pitchers pitch with a sprained (frayed or stretched) UCL much of the time. Sometimes, it's the point at which the muscles and tendons around the ligament can no longer absorb the excess force when the UCL finally tears.

What does all of this mean for Suzuki? Well, partially, it's just a good opportunity to clarify the terminology of injuries, There's certainly a real set of implications, though. It's a good thing that Suzuki doesn't have a strained hamstring or quad, or even damage to a tendon or the meniscus in his knee. A PCL sprain, in particular, is relatively easy to recover from for a rotational athlete like Suzuki. You'd rather have him dealing with this than with a muscle strain, and you'd rather it be the PCL (in the back of the knee) than the MCL or ACL.

I combed through Baseball Prospectus's Recovery Dashboard to create a useful guide by which we can estimate when Suzuki will return to play. The dashboard allows you to isolate injuries to the knee and to search the keyword "sprain", but that still leaves a bit of pruning to do. I cut out players who suffered their injuries in September, October, or over the offseason; those muddy any understanding of real recovery time. I went through and, where possible, removed players who turned out to have full tears of their ligaments after initially being diagnosed with a sprain. (That happened, for instance, with Dexter Fowler in 2021.) I also removed players I could verify were dealing with ACL or MCL injuries, leaving all cases of PCL trouble and the ones that were never publicly specified that well. Finally, I took catchers out of the sample. Any catcher dealing with a knee issue has a different checklist for returning to play than do other players, especially outfielder/designated hitter types like Suzuki.

Here are the relevant comps I was left with, going back to the start of the 2021 season.

Obviously, every injury is unique, just as every human body is. It would be foolish to overfit this data onto Suzuki's experience. (It also feels like something bigger was going on with Richie Palacios, doesn't it? If you strip out his tragic experience with this injury, the median and mean tighten even more, to 21 and 23 days, respectively.) However, these are fairly direct comps to Suzuki, and they tell a pretty clear story. Suzuki got hurt on March 14. We should expect him to miss anywhere from 3 weeks to a month of action, and since the team is pushing a fairly optimistic tone, we can aim for the early end of that window. Suzuki probably won't be ready for Opening Day, but he could be back in the lineup as soon as the second week of April, without having obviously rushed anything.

It feels like a good bet that he'll be the DH for a bit as he returns, though. He'll be able to get back into the lineup faster if he doesn't push himself to be ready to play right field regularly before doing so. Besides, Michael Conforto looks likely to make the team, so he can play right field while Suzuki is unavailable. 

If Suzuki does come back primarily as a DH, it will cramp the Cubs' style a bit when it comes to Moisés Ballesteros. This injury might end up nudging Ballesteros to Triple-A Iowa to begin the season, where he can soak up reps as a catcher and prepare to play that role for the parent club either later in this season or in ones to come. In the meantime, the Opening Day roster could include Conforto, the winner of the Dylan Carlson-Chas McCormick battle, and even Kevin Alcántara. When Suzuki returns, Alcántara could go back to Iowa, and once Suzuki is ready to resume active duty in the outfield, the team could jettison either Conforto or the Carlson/McCormick victor, calling up Ballesteros.

That arrangement would come with an ancillary benefit for the Cubs. If Ballesteros spends about 45 days in the minors this year, he'll come up short of a full year of service time by the end of the season, and the team will retain control of his services for 2033. It sounds like a small thing, but an extra year of team control is always a serious consideration for a team handling a top prospect. 

Suzuki won't be out an especially long time. It's just a sprain, and a mild one. His trajectory for the first six weeks of the season has been altered, though, and so might the Cubs' roster plans be. 

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