By whom? it would be unconstitutional.
No it wouldn't, the PGA could could simply demand a higher price from the major sponsors and NBC, which has a contract to televise the majority of the PGA tournaments could demand a substantial refund of the payments to the PGA for airing their tournaments. Such contracts are based on projected viewer numbers and if the top players are no longer on the tour, the audience numbers will drop as well revenues.
FWIW, advertising rates for pro sports such as the NFL are based on promised viewership. If the number of viewers drops, such as what has been happening in the NFL, the cost of the advertising goes down as well which results in a loss of advertising revenue to the NFL as well as to the network that airs their games.