Allen and the unbeaten Detonator Jack are faced with barrier 15 in their quest to give Ciaron Maher and David Eustace successive Derby victories and second Group 1 win in Adelaide in a matter of weeks after Snapdancer won last weekend's Sangster Stakes.
Allen landed his maiden Group 1 win aboard Howard Be Thy Name back in 2016 and has turned the race into his own in recent years.
Godolphin's Alegron drew barrier three with Damien Oliver booked to ride, as the stable opted for Adelaide over tackling the older horses, including last week's Port Adelaide Cup winner Splendiferous, in the Andrew Ramsden Stakes.
"He looks fit and ready for his target race, we were definitely tempted by the Andrew Ramsden, it's a shame the races clash," Cummings said.
Jason Holder returns to race riding following suspension to partner Son Of Emperor for the Mick Price and Michael Kent Jnr stable while Callan Murray has picked up the ride on King Of Pharaohs who will debut for new trainer Roslyn Day in the feature.
The Australasian Oaks winning combination of Trent Busuttin/Natalie Young, and Daniel Moor will chase another Adelaide major aboard Commander Harry who drew barrier eight.