Both Roglič and Pogačar came home today, to Slovenia. Likely a few days of self isolation and more or less indoor training is on the schedule. Currently in Slovenia you can't ride a bike in between two municipalities.
'No one is 100 per cent sure what the virus will do towards the summer' says Dutch Grand Tour specialist
www.cyclingnews.com
Dumoulin likely is in shape ATM, but can't do much with it. I remember Bernal saying he will rather rest for now, opting out of training.
I guess now the biggest challenge is to determine on when to start training again, for being in good shape till Tour. More should i guess be known in May. If Tour will get pushed to some later date, then in April one shouldn't train all that hard. If not, then not training much in April likely isn't the best option.