Probably not an equal position, White's game is freer, but Black has some development and isn't necessarily lost. The thing is that you are almost surely going to have to play ...c6 pretty soon to rescue the errant Knight on a5, and the immediate ...c6 gives Black a pretty good game where he gets to take advantage of White's disregard for time.
Why trade that for a cramped defensive game, even if it is solid? Just to save a pawn? That's miserly, great for saving your nuts for the winter if you are a squirrel, but chessplayers should be more adventurous.
aye.. but the squirrel survives and gets to play in the spring!
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 [Fried Liver Attack] 4. ... d5 5. exd5 5. Na5 6. Bb5+ Bd7
Why don't people play 6. ... Bd7
This way you avoid having to give up a pawn.
Example continuation:
7. Qe2 Bd6 8. Nf3 0-0
Seems like an equal position.
(I'm reading Andrew Soltis's Studying Chess Made Easy at the moment and he says 6. ... Bd7 is a "logical" move but "bad", the kind you'd play if you hadn't memorized the opening. But I have memorized the opening to that point and I'd still play it...)