John Slattery was in Pasadena, Calif., Saturday night at a press event to celebrate the return of “Mad Men’’ on AMC on March 25. But in between interviews and chatting with costars like Jon Hamm and Christina Hendricks, the Newton native was constantly checking his phone for the score of the Patriots game. He eagerly showed a reporter the update. The actor, who plays silver fox ad man Roger Sterling, was excited about the show’s return after such a long layoff but admitted that even he was a little confused about just where we left off in the award-winning period drama. “It’s funny because for [the viewers] it’s broken up into episodes. And for the actors you just have a scene you shot here and a scene you shot there and then six months later I can’t remember what episode what scene was in.’’ In addition to his role onscreen, Slattery also directed the fifth episode of the upcoming season. “It went over pretty well, so hopefully they’ll have me back,’’ he said of his return to the director’s chair. He hopes to take those skills to the big screen during his hiatus, for an adaptation he’s written of Pete Dexter’s novel “God’s Pocket.’’ At the moment, the actor says “the people I want to do it aren’t necessarily available the same time I am’’ but he’s hopeful to get the dark comedy going soon.