Nah, that's a myth based on the fact he was sometimes a sluggish starter when he wasn't on top form. In his record-breaking runs he was ahead of everyone by 20m. Obviously he eats up the distance from there on. This is the analysis below of his world record from 2009:
That's a field of the top 8 100m sprinters in the world and he's ahead of them all by just 20m. While the margins of difference between the fastest football player and a sprinter will be much less at 0-30m, fundamentally I don't think anyone outwith track and field could live with those figures.
Isn't that the old 'first two yards are in your head' thing they used to say about Kenny Dalglish. He was slow, but read the game better than anyone he came up against. Same for Baresi (who was quicker in fairness, but the point stands).