Some riders have been saying which GTs they are planning on before heading to the Olympics. It appears several have decided the Giro is the best option. This appears to include Nibali (definitely stated), Pogacar, and Bardet.
Those who are headed to the Tour are: Pinot, S Yates, Fuglsang and Valverde.

These are teams/riders who have made announcements.

Valverde has actually give a semi complete calendar saying his big goals are the classics (Ardennes), Tour, Olympics, Works and la Vuelta is sacred on the calendar. Thus meaning la Vuelta is a big goal. When pinned down with a question he said the Olympics is the biggest goals, but all of those races are big goals. Although Indurain was saying that Valverde likely would retire after the Olympics Valverde said absolutely not. That he's feeling great and just started his off season training and he feels as good as he did last year and there's no reason to retire while he's feeling this good. He said when he feels opposite of this and feels bad and isn't performing that's when it's time to hang up the bike. Then he said, but that isn't even crossing his mind. (He's getting annoyed with the retirement question).

Mr Unzue also said that Mas will be going to the Tour as race leader while Valverde will have a free role at the Tour.