Mets injury outlook: Jim Henderson and biceps tendinitis

Last week, the Mets placed relief pitcher Jim Henderson on the 15-day disabled list with right biceps tendinitis, adding on to the series of injuries they have encountered this season. This article will cover what that means and what Henderson faces going forward.

What is the injury?

A tendon is connective tissue that attaches muscle to bone. Tendinitis means that there is inflammation ("-itis" means inflammation) from the tendon as a result of overuse. The tissue fibers that create the tendon are supposed to align parallel to each other; if these fibers are mal-aligned and get jumbled, it causes irritation/pain and inflammation to the surrounding area. In this case, it is the shoulder since the biceps connect to two different places in the shoulder capsule.

Biceps tendinitis results from repetitive, abnormal stress on the tendon and is common for those who perform overhead activities (like pitching/throwing a baseball). Due to the repetitive motion, the tendon could consistently be pinched between 2 bones, rub over a prominent surface on a bone, or pulled on excessively to disrupt the fibers. The tendinitis could be the result of normal "wear and tear" or a product from overthrowing. When a pitcher overthrows, he tends to use bigger muscles (such as the biceps) to produce more force and increase the velocity of the pitch. It is not necessarily a flaw in his pitching mechanics but any flaw could contribute to placing abnormal stress on his biceps or any other muscles/ligaments that connect to the shoulder.

How long until Henderson returns to the bullpen?

It typically takes three weeks for changes in the muscle/tendon fibers to become permanent. After that point, it is about regaining strength back into his biceps and other shoulder/forearm muscles that may have weakened from inactivity. Henderson began a rehab assignment last night with the Double-A Binghamton Mets, ten days after he hit the DL.

Physical therapists can help facilitate the transition back to full health by using manual therapy, prescribing exercises and stretches, and using modalities (i.e ultrasound, electric stim, ice/heat). The lump sum of these effects will improve range of motion and joint mobility, increase strength, and reduce pain. To make improvements a little faster, doctors may provide a cortisone or PRP (platelet rich plasma) shot to reduce any lingering inflammation and promote tissue healing. It may take up to another two-to-four weeks for Henderson to return to pitching at a high level. Overall, we can expect Henderson to return around the All-Star break.