A man was seriously injured when he was struck by an uptown 2 train on the Upper West Side early Sunday morning, police said.

The man, whose identity was not released, fell to the tracks at around 1 a.m. just as the train was arriving at Central Park West and 96th Street.

“Looks like he lost his legs and if he hasn’t, he’s going to,” a law enforcement source said.

It’s unclear why he fell, but no criminality was suspected as the investigation began.

He was in serious condition at Saint Luke’s Hospital.