Here’s the only way this can work.
MLB takes over a massive baseball complex. You need at least 15 fields.
MLB buys out a bunch of local hotels, houses, fields, etc. Those locations are retrofitted/refurbished/built for player living.
Every player reports and is tested for COVID 19. By that point, the rapid test will be available. Any positives are sent home for a month.
Every player is isolated from any outside sources. No family, friends, nothing. It’s baseball, nothing but.
MLB staff, food services, and media are under the same quarantine.
2 weeks of ST, then opening the season. This should be done in a warm weather location so you can extend the season. Maybe northern Florida.
For the minor leagues, they’d do the same thing, and market the minor league games. The minor league complex would need to be driving distance from the MLB complex (within 3 hours). That way you can shuttle players from the minor if there are injuries.
Any injury requiring medical care is a 2 week injury. You need COVID testing to return and will be quarantined for awhile until they’re sure COVID doesn’t develop. If you have to break quarantine for care, you’re out.