Or maybe he had a mole removed. Or a root canal. [Update it was hernia surgery.]
Whatever the surgery, clearly it is in the past and Grella is on the mend.
The first competitive game of RBNY's 2017 is on February 22, when the Vancouver Whitecaps will visit Red Bull Arena for the first leg of a CONCACAF Champions League quarterfinal. The Red Bulls have three months to get themselves fit and ready for the first major test of the new season.
There is still an off-season to get through, including an Expansion Draft and the usual contract negotiations and trades. But as far as we know, Grella is penciled in for RBNY's 2017 campaign.
Get well soon, Mike.