This has not been the start to the 2018 season anyone anticipated for Clayton Kershaw. The once seemingly impervious-to-injury Kershaw has been on the disabled list since May 6 with tendinitis in his left biceps.
The issue reportedly first cropped up while he was playing catch the previous day. An MRI showed no structural damage and he resumed playing catch within a few days. He gradually increased his throwing distance and his effort without incident. Most recently, he progressed to throwing downhill with a scheduled 30-pitch bullpen session going nearly double the length. Next up is a simulated game scheduled for Saturday, and how he fares both during and after the session will likely determine the nature and the timing of the next step.
If he is able to progress without issue, he may not require a rehab assignment before he returns to the rotation. The plus side is Kershaw has had very little downtime from at least some level of throwing. Even when just playing catch, maintaining shoulder motion via light toss is valuable and may ultimately contribute to a shorter overall DL stay.
From an injury-analysis perspective, the concern is more of a general one for the Dodgers' ace, as he has had several injury issues of late (previously a recurring lumbar disc issue and now his throwing shoulder/arm). The culprit behind Kershaw's latest injury, the biceps tendon, attaches to the labrum and functions to add stability to the throwing shoulder.
A significant injury here has the potential to derail a thrower's career (all the more reason why the reports of no structural damage on imaging help alleviate major concern ... for now). And, Kershaw has not had his strongest start to the season, especially when it comes to giving up home runs. Ben Lindbergh of theringer.com cites a three-year consecutive drop in Kershaw's four-seamer fastball velocity -- with the biggest drop happening in 2018 -- as an indicator of progressive decline.
The numbers don't lie, but whether this is a long-term cause for concern from an injury standpoint is hard to say. Sometimes a change in velocity represents a subtle underlying injury, or pre-injury, or even fatigue. Sometimes the physical effort and/or mechanical adjustments a pitcher makes to overcome a dip in velocity can lead to injury.
Kershaw is also a 30-year-old pitcher who no doubt has some wear and tear associated with his pitching tenure (more accumulated microtrauma as a result of being so dependable for so many seasons, which translates into high volume pitching).
Is this episode the beginning of a relative decline, an indicator that he may not be able to deliver the volume year-over-year that he once did? Or, is this just a bump in the road that precedes a lengthy window that is uninterrupted by injury?
I don't think we know the answer to that just yet. But once Kershaw returns to major league competition we will begin to find out.