The visitors mustered just one shot on target as Daniel Harvie's 76th-minute strike proved the difference between the sides.
Rovers have won just two of their last 12 games and are now seven games without a victory away from home.
"Obviously, I am disappointed with the result," reflected manager Butler.
"I thought we stuck to the game-plan and did quite well out of possession but in the final third we were lacking any sort of creativity.
"The final pass wasn't there."
Doncaster scored twice in a 2-2 draw with Gillingham last weekend but apart from that fixture they have failed to find the net in four of their last five games.
Butler says that will be a focus in training this week as he looks to take his side back into the play-off spots after their defeat at MK Dons saw them slip to seventh in the League One table.
He added: "It is something we will address this week in training, giving them patterns of play to work to.
"We tell the players to express themselves in the final third, now we have to give them a plan and hope they execute it better than they have done today.
"I can't fault the players for their work-rate, it is just the final pass and the decision making wasn't there today."
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