I'm no lawyer, but it does seem probable the owners will have an extremely difficult time putting replacement players in place. This is a lockout, not a strike. The owners would need an overwhelming case against the players to accomplish this. The matter would be tied up in courts for a while. By then the league may be gone.
If the players decerify, then it gets easier. This is the reason I suspect most all of the players do not want to decertify.