Could be anywhere from 2-3 days depending on how the product was shipped from the ASC.
Overnight? It should arrive at Best Buy today.
2 Day? Should arrive at Best Buy on Sunday if the shipper delivers on Sundays, otherwise it will be Monday or Tuesday depending on whether the shipper considers weekends the same as week days.
I took an iPad in for service on a Monday. the ASC received it on Wed and shipped on Thur. I got the iPad back on Friday. But, that won't tell you much about when you will get your product back.
If the product does not arrive at Best Buy today, then you are looking at Monday or Tuesday as we already mentioned.
But.....maybe our experience has no relevance to yours and another user will have a different opinion.