An odd move, but Nakamura takes the rook off the dangerous diagonal and has his eye on Bc5 or Bb4.
1. c2c4  1... g8f6  2. b1c3  2... e7e5  3. g1f3  3... b8c6  4. d2d4 Carlsen likes the English Opening and plays it often, but the text move is a new weapon in his arsenal, as I haven't found any games of his with this move. 4... e5d4  5. f3d4  5... f8b4  6. g2g3  6... e8g8  7. f1g2  7... f8e8  8. e1g1  8... h7h6 This is a new move. Black normally captures the knight as soon as it's unpinned. 9. c3d5  9... f6d5 Black has to capture the knight. 10. c4d5  10... c6d4  11. d1d4 This position is strategically dangerous for Black, who runs the risk of becoming passive, while White exploits the better pawn structure and the semi-open c-file. 11... d8e7 [%c_effect e7;square;e7;type;Inaccuracy;persistent;true] 12. c1e3  12... b4d6  13. f1d1 [%c_effect d1;square;d1;type;GreatFind;persistent;true] A very good prophylactic move, avoiding the advance of the c-pawn. 13... b7b6  14. d4d2  14... a7a5  15. a1c1 