Browns rookie quarterback Johnny Manziel returned to campus Saturday and showed flashes of the improvisational wizard who took college football by storm the past two years. But this time “Manzielmania” enveloped the University of Akron instead of Texas A&M. Nevertheless, Johnny Football went back to school, and not even ornery weather could ruin his fun. Threats of thunderstorms prompted the Browns to run their Family Day scrimmage from 11:13 a.m. to 12:28 p.m. instead of the scheduled 11:30 a.m. to 2:10 p.m. But at least the announced crowd of 20,673 at InfoCision Stadium received an opportunity to watch Manziel do what he does best as the Browns took a test drive in preparation for their Saturday preseason opener at the Detroit Lions. In the first unscripted, live action of training camp, Manziel’s run-around-and-create-something-on-the-fly style was on display more than any other time since the Browns drafted him 22nd overall May 8. It’s his greatest strength, though it’s not always evident in a regular practice setting. “It felt good to run,” said Manziel, who won the Heisman Trophy in 2012. “And I think the plays we executed on those worked really well.” Manziel continued to work exclusively with the second-team offense, and veteran Brian Hoyer took all of the snaps with the first unit. Coach Mike Pettine said the staff would meet Sunday to discuss when it’ll give Manziel his first reps with the starters. On Thursday, Pettine and offensive coordinator Kyle Shanahan suggested it would happen soon.