Geraint Thomas' hopes of defending his Tour de France title suffered a blow on Wednesday as his road captain Luke Rowe was thrown out of the race ahead of three decisive mountain stages to come.

Rowe was expelled along with Jumbo-Visma's Tony Martin after the pair clashed during stage 17 from Pont du Gard to Gap.

Video footage showed Martin almost riding Rowe off the road with Rowe appearing to grab the German, though the exact order of events was unclear.

Either way, it was enough for UCI commissaires to send both riders home and fine them 1000 Swiss francs (#812) each.

The decision could have huge ramifications in the battle for the yellow jersey, with Rowe a key rider for defending champion Thomas and Martin a big part of Steven Kruijswijk's team.

Thomas sits second overall, 95 seconds behind Julian Alaphilippe, with Kruijswijk in third, a further 12 seconds back.

After the stage, both Rowe and Thomas had sought to play down the incident but to no avail.

To come here with this team, a bunch of good mates, I feel like I've let them down and of course let myself down.

Luke Rowe, Team Ineos

Ineos team principal Sir Dave Brailsford called the decision "severe".

It's nothing more than you see most days of the race. It's a pretty harsh decision.

Sir Dave Brailsford, Ineos team principal

Thomas is likely to feel the absence of his fellow Welshman more given their close friendship, although Rowe is not a climber and was expected to play a less pronounced role on the road in the decisive mountain stages to come.

But with the battle for yellow so close, this is still a significant setback for both Thomas and Kruijswijk, who were hoping to capitalise if Alaphilippe fades in the Alps, as is expected.

Thomas is now hoping that three big days at altitude, starting with Thursday's brutal stage 18 which includes climbs of the Col de Vars, Col d'Izoard and the Galibier, all above 2,000 metres, is finally enough to shake Alaphilippe off after he showed his first signs of weakness in the Pyrenees.

Obviously he wasn't great a couple of days ago. He's been racing well all race but you would think he'd be starting to get tired now. I guess teams will be thinking to try to make it hard all day. It'll be interesting, three big days. >

Geraint Thomas, Team Ineos