9/21/21, 6:42 PM







Bottom Line:
Gronkowski is back and looks to be as good as ever. But, 2020 was the first time since 2011 that he played in all 16 games. Combined with his injury history - particularly related to concussions, ACL, and spine - NFL data gives us high level of concern regarding his durability.

Major Injuries:
2009: herniated disc (L5-S1) w/nerve impingement, treated with surgery
2012: high ankle sprain, treated with surgery
2012 (Nov): broken forearm, complicated by infection; (6 games missed)
2013 (Jan): re-fractured forearm
2013 (May): herniated disc (L4-5) w/nerve impingement, treated with surgery; (6 games missed)
2013 (Dec): tore right ACL/MCL (knee), treated with surgery Jan 2014; also had “minor” concussion (9 games missed)
2015 (Nov): right knee bone bruise (1 game missed)
2016 (Aug): hamstring strain (2 games missed)
2016 (Nov): chest/lung contusion (1 game missed)
2016 (Nov): herniated disc w/nerve impingement (reportedly different disc), treated with surgery; (8 games missed)
2017 (Oct): thigh contusion (1 game missed)
2018 (Jan): concussion (1 game missed)
2018 (Oct): back strain, then returned and re-aggravated back (3 games missed)

Regular Season Games Played:
2010: 16/16
2011: 16/16
2012: 11/16
2013: 7/16
2014: 15/16
2015: 15/16
2016: 8/16
2017: 14/16
2018: 13/16
​2020: 16/16

Of Gronkowski’s prior injuries, only his 2013 knee injury (in which he tore his ACL and MCL) is directly associated with a long-term decrease in performance in NFL data, but this is expected to be have been stable for multiple years now. We have no reason to anticipate a further decline.

Gronkowski’s extensive injury history is worth breaking down one-by-one.

(1) His forearm fracture, though complicated by infection and re-fracture that required multiple surgeries at the time, is unlikely to cause further issues now.

(2) Regarding his concussion history, having one concussion makes him more likely to sustain another, and each is known to contribute to cumulative damage to the brain. Gronkowski has now had at least 2 minor concussions.

(3) The effect of his 2013 knee injury - which we know involved a torn ACL and MCL - depends on what other structures (cartilage and meniscus, which both help protect the joint) were injured at the time. While these details were not released, the involvement of multiple ligaments increases the likelihood that these additional structures also were injured. If this is the case, his career length and games played are both expected to be decreased compared to his uninjured peers, especially over the long-term.

(4) Finally, and perhaps most importantly, Gronkowski’s history of 3 disc herniations - when the cushion in between the bones of the spine moves out of place, exerts pressure on the adjacent nerve, and causes (potentially very severe) back and leg pain - raises significant red flags. Each time that he has had surgery, treatment involved removal of some portion of the affected disc. We have few comparisons because it is rare for NFL players to undergo this surgery 3 times, but the cumulative effect of repeatedly removing pieces of the discs is to increase the stress placed on the remaining ones. That unfortunately increases his risk of further injury to the lower spine area. If Gronkowski sustains another disc injury, he may need a surgery to fuse the bones in the lower spine, and likely would have to end his career.

Add in the fact that he’s missed at least 1 game in all but 3 years of his career, and this injury history leads to a very high level of durability concern for Gronkowski.

Image Source: Jeffrey Beall, CC BY 4.0