Diego Costa's return to Atletico Madrid will put Antoine Griezmann "on alert," midfielder Saul Niguez has said.
France international Griezmann continues to be linked with Manchester United, who made him a major transfer target in the summer window.
Costa's return has led to reports suggesting Atletico may need to sell to lower their wage bill because of La Liga financial controls, and sources told ESPN FC that United remain interested in Griezmann.
Speaking to Deportes Cuatro TV, Saul said Costa's arrival from Chelsea would ensure that Atletico's other forwards, who also include Vitolo, Angel Correa, Kevin Gameiro and Fernando Torres, remained on their toes.
"Costa's return will be good for everyone," he said. "For sure, he will put all the forwards on alert, including Griezmann."
Saul has regularly been linked with a move from Atletico, with United and Barcelona both reported to be long-term admirers.
But speaking to the Guardian, the Atleti fan said the long-term contract he signed last summer proved his commitment to the club.
"If you sign until 2026 it's because you mean it," he said. "It's not as if I've reached a level where I can't get better here.
"I want to give everything to be the best. The club is growing and there's still room to improve.
"It's like a family. And I have my parents, my brothers, friends, a partner who gives me tremendous stability. I have everything in life now."