I'm considering taking up the Breyer defence to the Ruy Lopez as Black and played an internet game which went
[StartPly "29"]
[White "White"]
[Black "Black"]
[FEN ""]
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. h3 O-O 9. c3 Nb8 10. d3 Bb7 11. Nbd2 Nbd7 12. Nf1 Re8 13. Ng3 Nc5 14. Bc2 Bf8 15. Bg5
This move 15.Bg5 is not in my book on the Ruy Lopez. The computer suggests 15...h6 16.Be3 d5 which doesn't seem right unless Black gets clear compensation for the pawn. All Black's minor pieces seem well placed except the Bishop on f8. What are Black's plans in this position?