The Greater Western Sydney co-captain is certain the clash between the two titans will play a significant factor when the Western Bulldogs visit Canberra's StarTrack Oval on Saturday.
Mumford hasn't taken long to hit top form since leaving the Sydney Swans for the GIANTS, last week amassing the third most hit-outs (60) ever recorded.
Predicted rain will only make his battle with current All-Australian ruckman Minson all the more crucial.
"Mumford playing against us last year caused us nightmares; it's obviously good having him in our team," Ward said.
"He and Minson are probably the two best ruckmen in the league at the moment."
Ward, who also played alongside Minson during his time at the Bulldogs, said the two players had a very similar style.
"All ruckmen are pretty big, but these two are actually really big, with huge chests and they really just crash packs," he said.
GIANTS head coach Leon Cameron was unfazed by forecasts of rain, pointing out his sixth-placed side had already played two of their three matches in the wet this year - including last week's five-goal win over Melbourne.
"We actually look forward to it (rain)," Cameron said.
"(Jonathon) Patton's probably kicking more goals in the wet than in the dry this year, and Jeremy (Cameron) is the same."
Following their first win of the season last week against Richmond, the 14th-placed Bulldogs have made three changes, including the return of in-form midfielder Koby Stevens.
Former Swan Jed Lamb will make his debut for the GIANTS while Liam Sumner will also play, the duo replacing the suspended Devon Smith and former Bulldog Dylan Addison.
