-Make starter tonight (Friday).
-Let ferment for 24 hours.
-Place in fridge Saturday night.
-Remove and decant Sunday morning.
-Brew Sunday afternoon.
What size starter is it? If it's not huge you'd be better off to leave it and pitch the whole thing on Sunday. It may not ferment out in 24 hours. The last lager starter I made took 4 days to ferment out.