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Alonso's teammate, Noah Syndergaard, underwent the procedure last week.
The 25-year-old slugger apparently took umbrage with the notion that athletes should be reluctant to go under the knife while health care systems across the United States are being ravaged by COVID-19 outbreaks.
"Medical supplies are high in demand," Alonso wrote. "The issue isn't Noah needing surgery and getting it. The issue I have is that the tone of this article suggests that players are making the decisions to get surgeries."
He added, "No athlete wants to go through a serious surgery and grueling recovery process. This surgery is done when it is absolutely necessary for their arm."
Several states have imposed bans on non-essential surgery in order to free up resources. Famed surgeon Dr. James Andrews has suspended all Tommy John procedures in compliance with Florida's executive order, but other specialists like Dr. Neal ElAttrache in Los Angeles continue to operate.