You get some of these moments with young QB's, it's part of the learning curve. The NFL is faster, the windows open and close faster, the defenders close down the QB and WR's faster. The decision making needs to be faster. The QB needs to pull the trigger on either A) the deep sideline throw, B) the wide open short throw, C) the mid-range out, or D) throwing the ball away. But youngsters often hesitate, and that's what happened here. Rosen will learn from this. He foolishly thinks he's athletically in the league with the defender, and in college he looks like a hero doing shiz like this, but in the NFL … he's very lucky not to have given up a Safety. As
@AnthonySabaNFL astutely points out, Rosen had options, and he needs his eyes and mind to process that play faster, then his decision making needs to remove that hesitation and play fast. I believe Rosen has it in him … but it'll take time.