I'm using Rosetta Stone, which is great, but it started off teaching me “el hombre” then suddenly switched to “al hombre”. I know al is a contraction of a el, but I can't understand when to use el vs al; e.g.:
Al hombre le gusta jugar el fútbol.
vs
El hombre come.
In your second example, 'hombre' is the subject of the verb 'comer', and hence does not need 'a'.
This answer gives more examples of this construction.
– jacobo Feb 06 '19 at 12:55