Unfortunately I don't think there is. Well, if you want to "hard-code" the final table size, then yes.
Assuming your final table has 10 seats:
<expression text="playersLeft - 10" format="number" precision="0">
The <expression> token was added in version 3, so this won't work in version 2.
I'll look into adding this as a legitimate layout token and/or conditions/formula variable.