You should know from being an NFL fan that fat doesn't equal slow. Warren Sapp ran a 4.7 40 yard.
Prince is in the worst shape of his life, and still cranked it up to 18.2 mph last season.
http://m.mlb.com/video/topic/7395516...o-tie-the-game
And yes, I know about acceleration. But it's not like any runner is going to suddenly gain a significant amount of speed over 20 yard splits.
Prince is still running a 4.5-4.6 40. Let's not forget that Ronaldo's time is from testing in lab conditions with artificial turf and Prince's 60 yard time was done in the real world on either grass or infield gravel (which doesn't have the best traction).