There's a scene in The Naked Gun that I don't get?

[pmalone4]

In the first Naked Gun movie, there's a scene where Frank is frisking all the ball players for weapons, and in one scene he takes of a player's hat and finds a thing of what looks like Vaseline in it.

Now, I may be incredibly stupid, but I just never really got it, so maybe someone could explain it to me?

 

[Matt Galdikas]

To make less friction

 

[Jason S]

pitchers have been known to put vaseline on their caps to throw better pitches-which isnt allowed