One of Robert Saleh’s first messages to Dalvin Cook rubbed the Jets’ new star running back the wrong way. 

The head coach presented Cook with a “worst-case scenario” during his first free-agency visit with the Jets, warning there might be stretches during which playing time could become scarce.

That’s mainly due to stud running back Breece Hall, whom the Jets drafted in the second round in 2022 and who appeared on his way to winning the Offensive Rookie of the Year Award before he tore his left ACL on Oct. 23. 

“When [Cook] left [the meetings] I was like, ‘There is no way after those, he is going to want to play here’ and he still wanted to be here, because it was laid out exactly,” Saleh said before practice on Saturday.

“I was like, ‘Why would he want to be here with the way we explained it?’ But he is all-in. And it gives us faith that he is all-in on this process and he is ready to do anything that we need to do to win football games.” 

Cook didn’t expect Saleh to disclose that conversation publicly, but he believes his response represents his ambition at this point in his career. 

“At first, it kind of bothered me a little bit,” Cook told The Post after practice. “But I went back and talked to my agent and thought about what he said. And then in my head I was like, ‘Opportunities I get, I have to take advantage of them.’ I was in their position recently — young talent. They’re ready to show why they were drafted. And I respect it. … 

“I know I’m gonna get on the field, but it was just processing how he told it to me. And I kind of respected it, how he told me, just being real with me. And it was one of those situations where you’re either gonna man up or you’re gonna run away from the situation. And me, I manned up. I want to come make [Hall] better.” 

Hall was activated from the physically unable to perform list and returned to practice on Aug. 15.

Both he and Cook are expected to be available for the Jets’ Week 1 clash with Buffalo on Monday night, though Saleh has avoided giving specifics on playing time. 

After he began his career as a lead back, Hall has no concerns about now sharing the backfield. 

“We’re probably gonna be the best duo in the league, so I’m not really too worried about that,” Hall said, adding that he and Cook already have a great relationship. “As long as we’re winning, then we’re both gonna be fine. We’re both some of the top playmakers on this roster.

“I think there’s gonna be enough footballs for both of us.”