Casey was forced to withdraw from the Players Championship with a back injury and has also not played at Wentworth since the extensive renovation programme which began days after Chris Wood's victory in 2016.
All 18 greens were reseeded with a new type of grass, while the greens on the eighth, 11th, 14th and 16th were completely rebuilt and another five - the third, fourth, fifth, 12th and 15th - were partially rebuilt.
A sub-air system as used at Augusta National was also installed, while all of the bunkers were redesigned and a total of 29 were removed.
Casey, who won this event in 2009 and the HSBC Match Play title on the West Course in 2006, said: "I'm genuinely excited. I've been looking forward to this for a long time and when we looked at the schedule and I rejoined the [European] Tour, this was an obvious event that I was going to put in.
"This event is really one of the main reasons why I became a professional golfer, coming down here and watching Seve and Lyle and Woosie and Langer and all those guys when I was a kid growing up.
"It has a special place in my heart so I can't explain how cool it is and how, touch wood, I will be good for tomorrow to tee it up again."
Withdrawing from the Players Championship actually helped Casey return to the world's top 10 for the first time since June 2011, but the back injury is an obvious concern as the 40-year-old looks to qualify for the Ryder Cup.
"I've had all the scans done and some weapons-grade anti-inflammatories have taken effect, but I haven't hit any golf balls," Casey added. "The last time I hit golf balls was last Friday and there was still pain, but we've done a lot since then.
"So I'm not worried. It's just the frustration of sitting around. If I'm not the worst-prepared player here this week something's wrong, because I've done absolutely nothing. I can't promise what this week is going to be like but I am chomping at the bit."
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