What Does Brewer Top Prospect Jeferson Quero's "Shoulder Subluxation" Injury Mean, Anyway?

According to general manager Matt Arnold, Milwaukee Brewers top prospect Jeferson Quero was diagnosed with a right shoulder subluxation on Monday. Quero suffered the injury diving back into first base during Nashville’s season-opening loss to Toledo. The Brewers are awaiting reduced inflammation before determining an appropriate course of action.

A shoulder subluxation occurs when the head of the humerus (i.e. “ball” of the arm bone) pops partially out of the glenoid fossa of the scapula (i.e. socket) before popping back in; this is known as relocating. A subluxation is the minor version of a shoulder dislocation, which occurs when the ball pops completely out of the socket and needs to be relocated by a doctor. (This is not to be confused with a shoulder separation, which occurs when the AC joint at the tip of the shoulder is disrupted, causing the scapula (i.e. shoulder blade) to separate from the clavicle (i.e. collar bone).)

Recovery timelines following a shoulder subluxation vary significantly depending on the extent of collateral tissue damage. The ligamentous structures that hold the humerus in place are “over-stretched” during a subluxation. Additionally, the glenoid labrum, a ring of cartilage that helps hold the humerus in place and increase the stability of the shoulder, may also be damaged. If the damage to the ligaments and labrum is present and significant, surgical intervention may be required to prevent recurrent subluxations or future dislocation. 

However, most subluxations do not result in significant ligament or labral damage, especially if minor. Restoring any lost range of motion and strengthening the shoulder musculature is often enough to return to play. According to Baseball Prospectus’s Recovery Dashboard, the average number of days missed following a shoulder subluxation among hitters is 69 days, though that number is inflated due to some athletes eventually undergoing labrum repairs and/or suffering severe injuries. Remove those from the data set and the average number of days missed for mild or moderate subluxations drops to 35.

Expect Quero to land on the IL and to be there for some time. If the inflammation reduces quickly and there is no sign of further damage, he should return to play within the next 1-2 months. In the short term, this is a blow for Quero and the Brewers. However, if there is no further damage it should not impact his overall standing as one of the top prospects in baseball. A worst-case scenario is that imaging reveals a labrum tear, which would sideline him for 4-6 months if surgically repaired. But even then, Quero’s future would remain very bright.

Interested in learning more about the Milwaukee Brewers' top prospects? Check out our comprehensive top prospects list that includes up-to-date stats, articles and videos about every prospect, scouting reports, and more!