Whenever Origin updates itself, I check if the settings have reset. I often have the auto updating unchecked. After what happened with Sims3 patch 1.67, I learned my lesson the hard way.
To answer whether you can play sims4 from the Origin launcher without patching, the answer is yes (as long as you haven't started any update, even 0%).
All you need to do is open Origin, and Go Offline. Then click your game to play. It would be even much safer if you turn off your computer/laptop's wifi.
I discovered this by accident. I was staying at my mom's place and was playing fine. She has no internet, so no updates or whatever. Therefore, logic tells me, that if I simply play with Origin offline, it is okay not to patch until I'm ready. This is what I did with the latest patch. It was a day after the patch release before I patched, but I could still play the game.
I hope this helps someone.