Valverde, who turns 37 on Tuesday, has been in blistering form since the start of the season, winning stage races and one-day events in unstoppable fashion. Last week he won La Flèche Wallonne and Liège-Bastogne-Liège to cement his palmares as one of the most successful riders in the last 25 years and although he has only one Grand Tour to his name – the 2009 Vuelta a España – Froome thinks that the Movistar man can challenge for the yellow jersey.
"He's been in formidable shape so far this season. I can only take my hat off to the way that he's raced so far," Froome told the media at a press conference on the eve of the Tour de Romandie.
With Movistar's Nairo Quintana set to challenge for the maglia rosa at the Giro d'Italia, the Spanish squad's Tour de France plans are still to be decided. Quintana has already stated that he will ride the Giro and the Tour but no rider has been able to win the double since the late Marco Pantani in 1998. Valverde has stood on the Tour de France podium before – alongside Froome and Quintana in 2015 – but he has never quite been able to mount a concerted GC challenge for the yellow jersey.
"He's normally a rider who is normally up there in the Grand Tours and I imagine this season more than ever that he's going to be motivated to go for it in the Tour, especially if he's not doing the Giro," Froome said.
"He's a rider who races right until the end of the year at really good level but this year he seems to be even more up there. The Classics have just highlighted that even more."
Froome pointed to this year's Tour de France route, which potentially favours an in-form Valverde over the three-time race winner from Team Sky.
"When you come to the last kilometre with him, you know that he's got a savage acceleration. You don't want to be coming to the line with him.
"It remains to be seen as to what Movistar's strategy is coming into the Tour but if Valverde keeps up this kind of form then he's going to be the guy to beat in July as well. Especially on a Tour route that might depend more on bonus seconds. We don't quite have the same number of mountain stages in this year's Tour and it might come down to bonus seconds."
When asked if Valverde could maintain his form, which has seen him win consistently since February, Froome pointed to one if his own previous campaigns: "In 2013 I was able to hold my form from Oman right through until the end of the Tour, so I don't see why not."