The Reds won just two of nine matches during July and August last season to eventually finish 11th overall and the skipper wants that period of the season to change for the good.
"In July and August, when the best teams hit their stride, we've always seemed to take a step back - it's like we don't have enough in the tank," said De Rosario. "And July and August is the most important time of the year."
Under new coach Aron Winter, TFC will be hoping to improve their table position this season and finish higher than their MLS best of 11th.
Since 2007, the Canadian club have finished 13th and 12th on two occasions before last year's slight rise and they will be looking to improve even further in 2011.