The pair attempted attacks on Thursday’s stage up the Col du Glandon but couldn’t escape from Froome, while Nairo Quintana has also failed to pull any time back on the yellow jersey holder.
With three categorised climbs before the ascent of La Toussuire, Thomas expects to see the breakaway play a prominent role once more, but believes the showdown will occur on the final climb.
“There is always somebody in the top seven or eight who can still be pretty dangerous on a stage like this, even if they are four or five minutes down,” he told the BBC. “It’s only 138km long, so it’s not a huge day in the mountains and you can ride hard. I think it will be full-gas racing from start to finish.
“And Team Sky might do the same. When it comes to the final climb, each of the big contenders could have a good carrot to chase, what with the time bonus for the stage win, and people to help them down the road. We should see a big showdown.”
Quintana and Alejandro Valverde sit 3:10 and 4:09 down on Froome respectively in second and third, with Thomas sitting 6:34 back in fourth.
Your guide to the Tour de France in the Alps