The hardest ball to track is the line drive hit right at your face. Can't tell whether it's going over your head or landing 15 yards in front of you. Even tougher when it's a knuckling softball. A ball elevated and going directly over your head isn't very tough. I have a much easier time fielding those than line drives or balls slicing, hooking, or seriously affected by wind. All that said, I can't imagine what Tebow saw that made his route sensible. I've taken a bad first step in before based on the hitters hips, reach, or pitch location. I've never run in on a ball mashed like that. You just can't be paying attention very well if you do.