It appears that Delta is putting a 767-300 on the MSP-PHX route beginning December 3rd. It will operate ad DL2392 departing MSP at 0900 and arriving PHX at 1133. The return flight will depart PHX at 1235 and arrive at MSP at 1641. An interesting development that I could not find any info on.
Back in the day, NW frequently flew DC-10’s on MSP-PHX during the winter peak. It’s a huge market and US Airways doesn’t have any larger equipment to deploy to it available from the PHX base and Sun Country’s fleet is stretched to the max during that time of year as well, so the capacity growth has to come from Delta.