The Nationals placed Millas on the 10-day injured list Wednesday with a fractured left index finger.
The move is retroactive to July 12. Millas was removed from Washington's July 11 game in the ninth inning, when he presumably suffered the injury. Millas has slashed .185/.277/.262 with two homers, 11 RBI, 18 runs scored and a 14:37 BB:K across 152 plate appearances as the Nationals' No. 2 catcher.