First reported on Monday night by the Daily Telegraph, McIlroy’s link up with Cowen has now been officially confirmed as he prepares for this week’s WGC-Dell Technologies Match Play in Texas.
"Pete is an addition to Rory's performance team,'' Sean O'Flaherty, McIlroy's agent, wrote in a text message to ESPN as the development unfolded.
Cowen, who also currently works with Brooks Koepka and Henrik Stenson, had given advice to McIlroy recently during both the Arnold Palmer Invitational and the Players Championship.
That was in an unofficial capacity, but now the 70-year-old Yorkshireman is formally on board as McIlroy’s latest bid to become just the sixth player to complete golf’s career grand slam looms large.
McIlroy, who faces his Ryder Cup team-mate Ian Poulter in Wednesday’s opening round of round-robin matches in the WGC event at Austin Country Club, has been coached by Michael Bannon since he was eight years old.
That connection came about through Bannon having been the head professional at Holywood Golf Club outside Belfast, where McIlroy cut his golfing teeth.
It remains to be seen if Bannon, who helped his compatriot win four majors, will still have a role to play in that performance team referred to by O’Flaherty, with McIlroy not scheduled to stage a pre-tournament press conference today in Texas.
A stuttering run of form - the 31-year-old has not won since landing the WGC-HSBC Champions in China in November 2019 - is the main reason behind McIlroy believing the time is right for a fresh pair of eyes in terms of the technical advice being offered to him.
At the same time, though, it seems that the impact of the Covid-19 pandemic has also been a factor, with Bannon unable to travel to the US to work with McIlroy as freely as he did previously.
Cowen, in contrast, attends most of the big tournaments and now one of his main tasks will be to try and get McIlroy back in the sort of form that landed him two majors and a WGC in three starts on the trot in 2014.
This time last year, McIlroy was back riding high as the world No 1 but has now dropped to 11th, having struggled to find any sort of consistency since the PGA Tour came out of its Covid lockdown last June.
He opened his 2021 campaign with a brilliant 64 in the Abu Dhabi HSBC Championship on the European Tour in January before having to settle for third spot behind Englishman Tyrrell Hatton in the Middle East.
He has since missed the cut twice in four events on the PGA Tour, most recently after he opened with a disastrous 79 as the defending champion in the Players Championship. That was the worst opening round by a title holder in the event since Sandy Lyle signed for the same score in 1988.
In the wake of that disappointment, McIlroy made an eye-raising admission as he said that his "swing issues” had been down to trying to keep up with Bryson DeChambeau after seeing the American overpower Winged Foot to win the US Open last September.
"I'd be lying if I said it wasn't anything to do with what Bryson did at the US Open,'' he said of DeChambeau’s six-shot success on one of the toughest courses in the game. "I think a lot of people saw that and were like, ‘whoa, if this is the way they're going to set golf courses up in the future, it helps. It really helps’.
"The one thing that people don't appreciate is how good Bryson is out of the rough. Not only because of how upright he is but because his short irons are longer than standard, so he can get a little more speed through the rough than us, than other guys.
"And I thought being able to get some more speed is a good thing, and maybe to the detriment a little bit of my swing, I got there, but I just need to maybe rein it back in a little bit.”
Cowen was involved with Scottish Golf Support Ltd (SGSL) following its launch in 2010 to try and help the country’s young professionals fulfil their potential before the initiative withered on the vine.
He also has worked with major winners Graeme McDowell, Danny Willett, Darren Clarke, Louis Oosthuizen and Sergio Garcia, as well as Ian Poulter.
McIlroy, the 2015 winner, faces Poulter in the first of 32 matches on Wednesday in Austin, where other tasty group openers include Westwood taking on Garcia and Matt Fitzpatrick locking horns with Texan Jordan Spieth.
Though reluctant to use it as an excuse, Spieth has revealed that a chipped bone in his left hand probably contributed to the form slump that following his 2017 Open Championship win at Royal Birkdale.
"It was something that [if] you can clean it out, it's not going to make anything worse,'' he said. "It's just a matter of how bad it's bugging you and it was for a while there. Kind of in the spring of 2018 through that fall, and then it got a little better probably because I started swinging so poorly.
"I don't feel it now, which is nice. Needed to work on some grip strength stuff. For the most part I started noticing it when [coach] Cameron [McCormick] was trying to get my grip strengthened and I just kept fighting him on it because it would hurt. I didn't really know what to do and I just ended up playing through it.''
Bob MacIntyre makes his debut in the event in the final match on the opening day against American Kevin Na, starting at 8.11pm in a group that also includes world No 1 Dustin Johnson.