The 24-year-old found the net five times in six games last month after moving into a more central role for the Millers.
Manager Steve Evans said: "This is just what the lad deserves. He's got 25 goals this season and 90% of those coming when he's played from a wide position.
"Unless you're scoring four a game, to get as many goals as him you need to be spreading them over the course of the season and he's been consistently good."
Rotherham currently sit fifth in the league table with one game left to play away to Swindon Town.