The Yankees will be without one of their new stars for the start of the 2023 MLB season.

Carlos Rodon has a mild left forearm strain, Brian Cashman told reporters, and he will not be ready for Opening Day.

The left-hander will not throw for seven to 10 days and will be on the injured list to begin the year.

Rodon’s UCL is fine, according to Cashman.

Rodon was scheduled to throw a bullpen session on Wednesday, which was then pushed to Thursday, before going for an MRI that revealed the forearm strain, The Post’s Greg Joyce reports.

It is a significant blow for the Yankees, who signed Rodon to a six-year, $162 million contract in December to help fortify their rotation.

Rodon, 30, earned his second consecutive All-Star nod last season, pitching to a 2.88 ERA with 237 strikeouts in 178 innings with the Giants after seven seasons with the White Sox.

He previously underwent Tommy John surgery in 2019 and missed time with a shoulder injury in 2018.

The Yankees are already without another starting pitcher in Frankie Montas, who underwent shoulder surgery and isn’t expected back until August at the earliest.

Montas revealed Wednesday that he wasn’t 100 percent when the Yankees traded for him last year.

The right-hander also said he has “no doubt” he’ll be able to pitch later this season.

Cashman also told reporters that relievers Tommy Kahnle and Lou Trivino will also begin the season on the injured list.