As the In-Season bidding rules plainly state:
"If a player's 24 hour challenge period hasn't expired prior to 11:59pm on Saturday, bidding on that player will suspend until the following Tuesday at 12:00am when the 24 hour clock will resume."
Thursday games throw a loop into things, but Sunday games have always been pretty clear.
The clock definitely does not wait for me to give you a thumb...its up to each owner to manage his own roster and transactions...
Here's the link to the rule book, for when you are confused in the future:
http://sacd.predsff.com/OfficialSACDRules.html