Twins Ace Pablo López Diagnosed with Grade 2 Teres Major Strain: How Long Will He Be Out?

The Twins received tough news Wednesday night, when an MRI revealed that starting pitcher Pablo López suffered a Grade 2 teres major strain. Dan Hayes of The Athletic reported that the Twins expect López to miss the next 8-12 weeks.

Unfortunately, the Twins' starting rotation isn't unfamiliar with this injury. It's the same one that ended Joe Ryan's 2024 campaign last August. The teres major is a muscle located at the back of the shoulder, running from the shoulder blade to the front of the humerus, or upper arm bone. Its role is to extend and internally rotate the arm; in layman's terms, it's an important muscle for throwing a baseball at a high velocity. This is the same role as the latissimus dorsi, more commonly referred to as the lat, and the two muscles are located right next to each other. Without imaging, such as an MRI, it can be difficult to differentiate between an injury in the two muscles; hence the initial diagnosis of a lat strain.

"Grade 2" simply means that the injury is of moderate severity. From a technical standpoint, it means that a significant amount of muscle fibers were torn, though the overall integrity of the muscle remains intact. This is not an injury that requires surgery, but it's not uncommon for athletes to receive a platelet-rich plasma (PRP) injection in an attempt to aid the healing process. 

According to Baseball Prospectus's Recovery Dashboard, the average time to return to play following a teres major strain is 78 days, and the median is 73. That's right in line with the Twins' estimated timeline, though on the longer end of it.

Grade 2 strains are generally a months-long injury, regardless of the muscle involved, which is in line with the Twins' 8-12 week prognosis, though it will also take some time for López to build back up after being on the shelf. According to Hayes, López is not expected to throw for at least four weeks, which is typical for this type of injury.

While this is undeniably a tough blow for López and the Twins, as long as the recovery goes well, there shouldn't be too much of a concern long-term. As previously stated, this is the same injury suffered by Joe Ryan last season, and he has been among the best pitchers in baseball this season. Given a smooth recovery, López should return by sometime in August or September, in plenty of time for a Twins playoff push. That's a long time from now, though, and his absence will be deeply felt as the trade deadline approaches.