Red Bull-BORA-hansgrohe's Roglic won his fourth Vuelta title in 2024 to move level with Spaniard Roberto Heras, but the 36-year-old has not seen the same level of success at the Tour de France, coming closest in 2020 when he finished runner-up behind compatriot Tadej Pogacar.
He finished eighth overall this year, well behind Pogacar, who lifted his fourth Tour de France title in July.
On Wednesday, Red Bull-BORA-hansgrohe confirmed their Tour de France campaign would be spearheaded by Belgian Remco Evenepoel and German Florian Lipowitz.
Asked about the decision, Roglic told reporters: "(If) I can choose one race to win, I would sign the Tour de France.
"I mean, it's not a secret, but as I said, the reality is different. The level that I was finishing was different, and the first point to consider about myself is how to find the way to be competitive and compete for victories and focus my energy and everything only on that – the rest will follow.
"If you ask me straight, for results, if I'm second in the general classification of the Tour or winning the Vuelta, what will I choose? I (would) win the Vuelta, it's simple."
Roglic, the Tokyo 2020 Olympic time trial champion, also won the Giro d'Italia in 2023.
