I listened carefully to what SD had to say (how many of the Twitterati did, I wonder?) and he was careful to stress that this was not a demand, or even a proposal. Rather he was "putting it out there" as a suggestion for further debate, whilst ackowledging freely that it was for the (real) experts to decide.
He also stressed that urgent priority groups must still get the vaccine first, but that once they were satisfied, then perhaps footballers might be moved up to the next groups, whilst diverting to the NHS the money which Football is currently spending on testing.