The last of McIlroy's four major titles to date came in the 2014 US PGA at Valhalla, since when he has recorded 10 top-10 finishes in the game's four biggest events without success.
Four wins in 2019 and a top-three finish in his first event of 2020 saw McIlroy back to world number one for the first time since September 2015, but he was overtaken by Jon Rahm and Justin Thomas following their respective wins in the Memorial Tournament and WGC-FedEx St Jude Invitational.
Mcllroy admits he has found it "easy to lose focus" while playing tournaments without fans, but three-time European Tour winner Dougherty told the PA news agency: "I do think the majors will maybe tick that focus box for him.
"Going into the PGA will be useful for him. It's quite a beefy golf course still, he's got a great feeling on that golf course, it suits his eye and if he has a good driving week there's no reason why he won't contend and he'll be spurred on by the fact that he's been taken off the world number one spot.
"That's what I liked about Rahm a few weeks ago. He said 'I'm desperate to be number one, I really want it and I'm not going to pretend'.
"I get why players don't say they do, but knowing Rory he knows what his position should be and it's on top of the game. He has that ability to stretch out in front of the pack so I imagine he'll be spurred on by that."
McIlroy won the WGC-Cadillac Match Play at Harding Park in 2015 but comes into the first major of the year having recorded a best finish of 11th in his five events since the PGA Tour returned to action following the Covid-19 shutdown.
"His iron play has dropped off," Dougherty added. "His strokes-gained-approach (ranking) is a long way down from where he was. He was third going into lockdown. He's still near the top of the driving stats but his iron play has dropped off a bit.
"Without the crowds there it's a weird time for everybody and we almost have to cut them all a bit of slack. It's easy to say he needs to be better than that, but we've never seen anything like this in our lifetimes."
McIlroy was due to begin his first round at 0833 local time (1633BST) alongside Thomas and Tiger Woods, with Brooks Koepka getting his campaign for a historic third straight win under way at 0811 local time (1611BST) alongside fellow major champions Shane Lowry and Gary Woodland.