Allen said in March that he hadn't really formed an opinion on the Nittany Lions. But after a visit to spring practice -- and a closer look at the facilities, tempo and staff -- the 2014 prospect said his entire outlook had changed.
PSU became a favorite in a short period of time, and he was at the Blue-White Game last month talking to commits like Mark Allen. Marcus previously said that early playing time with PSU was also a positive.
"They showed me the depth chart and said I could make an impact," he said. "They didn't say I would get a starting position -- no school would tell me that -- but they said the opportunity to play early is really high. So I know if I work my butt off in the weight room and classroom, then I can get that job."
Allen finished his junior season with 69 tackles (39 solo), two interceptions, two forced fumbles and two fumble recoveries. The former linebacker also deflected nine passes.
The 6-foot-2, 190-pound prospect holds more than 20 offers. He chose Penn State over schools such as Clemson, Georgia Tech, Nebraska, Pitt and Rutgers.
He is the second defensive back of the 2014 class, the first of whom, Daquan Worley, came just last week.