Dozens of NFL scouts converged on USC today for the school’s pro day, an opportunity for draft prospects to showcase their skills. It was a big day for linebacker Keith Rivers, a potential top-10 pick who was particularly impressive in the vertical leap and 40-yard dash. He ran the 40 in an announced 4.51 seconds — although the results of scouts varied — and actually reached higher than the top end of the vertical-leap pole. His leap was measured at a remarkable 42 1/2 inches.