That is a novelty. The rook move can be used for doubling on either the c- or the d-files. Or maybe even for a kingside attack.
1. d2d4  1... d7d5  2. c2c4  2... e7e6  3. b1c3  3... h7h6 A cunning line, played regularly by Carlsen among other top players. 4. g1f3  4... g8f6  5. e2e3 Sevian decided to keep his dark-squared bishop behind the pawn chain. 5... f8d6 Here too, the bishop can be developed more powerfully. 6. b2b3  6... e8g8  7. c1b2  7... b7b6  8. f1d3  8... c8b7  9. e1g1  9... b8d7 In a symmetrical position both players start to prepare for the inevitable central clash. The c7-c5 and e6-e5 breaks are on the agenda and both sides try to anticipate the future. 10. a1c1  10... a7a6 Nihal prefers to keep his options open and takes away the b5-square from the enemy knight.