Froome's inclusion means that Team Sky principal Dave Brailsford has left out former Tour champion Bradley Wiggins, despite the Olympic Gold medallist showing his form winning Thursday's British national time trial title on the roads of Monmouthshire.
Thomas will play a key role in Sky's attempts to claim a third straight Tour win as Froome's chief sidekick throughout the three week race.
For now though Thomas must continue to play second fiddle for the 21 stage race, that finishes just seven days before he attempts to secure a victory of his own at the Commonwealth Games road race in Glasgow.
'It's certainly not ideal. It's a big three weeks of racing around France trying to help Froomey win really so it'll be tough for sure" he said.
"I think mentally it's ok because I know I've just got to keep going until the Sunday, just hopefully I can recover well, eat well, sleep well and that's pretty much all I can do go there and go as fast as we can."