Smith said he was born with the issue, but his "severely enlarged" heart - a potentially life-threatening issue - was only discovered after he underwent additional testing following his positive COVID-19 test.
"There is a surgery that will allow me to continue to play football as soon as I am healed and cleared and I didn't think twice about going with that one," Smith wrote. "By no means am I ready to be done playing football, there is still so much more I want to accomplish on the field."
The 23-year-old was Minnesota's fifth-round pick out of USC in 2019. Smith appeared in five games for the Vikings in 2019 and registered six tackles.