Dennis confirmed his slim Tour de France chances after winning both the prologue and final time trial at the Tour de Suisse and holding the leader's jersey for a day.
At this stage, it appears BMC is sticking to its season-long plan for Dennis despite his early abandon at the Giro d'Italia due to injury.
Without the hard three weeks of Italian Grand Tour racing in his legs, there was hope the Australian time trial champion would adjust his season schedule and ride in support of compatriot Porte in his bid to win the Tour but that now seems unlikely.
“I’m still a reserve,” Dennis told Cyclingpro.net. “At this moment I’ll be staying at home and that’s what the plan was. To do the Giro.
"I would love to be there for Richie, he's a good friend and to try and help him win would be amazing.
“It would be a dream come true, even if I’m not wearing yellow, to ride down the Champs-Élysées with the yellow jersey in my team.
“[But] At this stage, I don’t think I’m going and I’ll be cheering them on from my couch and enjoying a nice cold drink."
Dennis also claimed a time trial stage at the Tirreno–Adriatico earlier this season and would have been a strong favourite for the Tour de France opener in Dusseldorf, with Katusha-Alpecin's German star Tony Martin his closest rival, but he said Stefan Küng is the rider poised to take a starting spot.
“I’m sure they [BMC] are thinking of that yellow jersey in Dusseldorf, but Küng is on the list in front of me and he’s put his hand up since December.
“He’s a good possibility to win in Dusseldorf and if it's me or him it doesn’t matter, as long as we’re wearing the BMC jersey then it’s successful for us.
Looking ahead to his post-Tour schedule, Dennis is now eying a spot at the Vuelta a España and later UCI Road World Championships.
“I’d love to do the Vuelta and I think that’s great preparation for the worlds in Norway this year.
“I still have to see what the team wants but either way it could be a good outcome for me and the next couple of months can be really exciting.”