This move prevents the pin with Bg5, but for me it's not clear that it's necessary. Black could castle or immediately begin his traditional plan on the queenside with b6-Ba6.
1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. f2f3 An extremely dynamic, creative and risky opening system, matching Arjun's playing style. 4... c7c5  5. a2a3  5... b4c3  6. b2c3  6... b8c6  7. e2e4  7... d7d6 A typical Nimzo-Indian pawn structure. I've always liked Black in this type of position. 8. g1e2 