Tom Selleck, outfitted in a cap and jersey No. 14, took batting practice with the Baltimore Orioles Sunday and was the target of a little baseball humor. The athletic "Magnum, P.I." star, who once was a basketball player at USC, is in Baltimore making a movie, "Her Alibi." He showed up at Memorial Stadium Sunday to take a few swings, hitting a couple of batting-practice home runs. However, he made the mistake of putting off two Minnesota Twins, Al Newman and Mark Davidson, when they asked for his autograph. So Newman found a towel, filled it with shaving cream and left it where Selleck would be sure to grab it. Sure enough, when Selleck finished hitting, he went for the towel and wiped shaving cream all over his face. "I got my revenge," Newman said.