Yes Frosty you can do that, but that counts as another 'use' for that player, as signified by the 3 dots below them.
My scoring has been bad too, lol, bench scoring better than on field players, swap em back again and it goes the other way again, haha, always the way. These fedex cup playo*** are only for practice and getting used to it. The regular season you'll have to think a bit more about spacing out your 3 uses per player over each segment by what tournaments they've done well in in the past.
I usually google PGA Tour results and you can look back on past tournament results over years and see how many top 10's a player had previous, the main thing is trying not to be in a position where you can't field 4 players for the 4 rounds, that's when you really lose ground.