Yeah you can do that.
Basically there is a salary floor, to stop people from running teams with 3 $1000 players all season.
If you think it will help your team to have another 19k in salaries actually playing, and the capital outlay to purchase those players then by all means do so.
But if your team is going to be in a losing situation regardless, I'd just save the money that you would otherwise spend on new players