Thats the 1st thing they shook was liability. Now if the NFL was to ensure these multi-millionaires with a guarantee that they will hold them down if something happened to them due to the vaccine; then that would be different. However; they would never do that, so its easy to talk tough. Put the money where their mouth is; how strongly do you believe in this treatment?
The NFL players union is weak. They won't unite against the virus cause they won't even sacrifice for better contractual conditions for themselves. They had an opportunity when the pandemic first started to stop play and force the league to guarantee contracts. They will stay on the losing end as long as the players are deemed as replaceable parts (next man up syndrome) and not valued athletes.