Kershaw was scratched from his Sunday start, according to Ken Gurnick of MLB.com, due to inflammation in his upper back/shoulder area. The Dodgers are not sure when he will be back and have not ruled out the disabled list.
Dylan Hernandez of the Los Angeles Times had the first report on specifics:
Clayton Kershaw expressed his frustration with being scratched, but does not believe it to be too serious at this time—according to the Dodgers' official Twitter account:
The teres major is a muscle that can be described as either the shoulder or back. It connects between the torso and the upper arm and has two main functions. It helps rotate the arm and, as importantly, helps stabilize the shoulder.
Studies have shown that it is involved with pitch velocity as well. It is often confused with the teres minor, which is one of the four muscles of the rotator cuff. While the names are similar and they are in similar locations, they have very different functions and outcomes.
You may remember that this is the same muscle that pushed Jurickson Profar of the Texas Rangers to the DL. While both throw, there are obvious differences in how they throw. There is also a difference in how significant the strains are. Profar has a Grade II+ strain, while the Dodgers call Kershaw's injury "inflammation." That signals that if this is a strain, it is minor, perhaps a Grade I.
However, this may not be a strain at all. The teres major is separated from the latissimus dorsi by a bursa sac. If the muscles get out of alignment, that bursa can become irritated and inflamed. While the Dodgers and team sources would not confirm the exact nature of the injury, it remains a possibility. If the inflammation can be contained and reduced quickly, his recovery time may be somewhat shortened.
Either way, there's a broad range of timelines for Kershaw's return, but the Dodgers will need to understand exactly what the issue is (which I am sure they already do) and then find the root cause. A minor muscle strain in and of itself is not a major concern, but something like scapular dyskinesis could be a major concern.
Since Kershaw made one very solid start, it's harder to say that this injury has anything to do with the early start and the trip to Australia.
Kershaw certainly looked as good as he did last season, dominating the Diamondbacks with his normal command, control and velocity. There was no indication of any physical problems during the start or immediately after. However, Kershaw would not tell the media if he felt any discomfort in that start.
The Dodgers could place Kershaw on the DL retroactive to that start, meaning Kershaw could return on April 6, but that would mean he would not make it back for the Dodgers' first home game. The Dodgers haven't indicated they will DL him, and there's not a necessary roster move. Teams do like to delay decisions and carry a "26th man" when possible.
The Dodgers did not announce who will make the Sunday start. The Dodgers won't use Zack Greinke, who is coming back from an injury of his own, a mild calf strain that set him back just enough to miss the Australian trip that started the Dodgers season.
Instead, Greinke will stay on track for his Tuesday start. They're also unlikely to use Hyun-Jin Ryu in the opening series as he works his way back from a toe problem. Dan Haren is the most likely possibility with Paul Maholm another option.
The Dodgers have some depth issues behind Greinke to make it through without Kershaw, though the talent dropoff is steep. If Kershaw is placed on the DL, it could free up a slot on the active roster for Zach Lee, one of their top pitching prospects. Josh Beckett won't be ready until mid-April, and the team had hoped to get through the first few weeks with a four-man rotation.
The Dodgers have the talent to be back in the playoffs, but they'll have to be healthy. With a number of pitchers fighting their way back and their top two struggling with what the team hopes are minor injuries, it's not the best start. The Dodgers' medical staff is smart to be cautious, but it's definitely concerning to see the season start this way.