e6 is the most common response, and a solid, though perhaps insipid move. It does leave the knight pinned, and play into white's plans, leaving e5 as a prime destination for white's knight. Black's will almost certainly have to play Be7 at some point too.

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1. d4 Nf6 2. Nf3 d5 3. Bg5 e6

• Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.