Rory McIlroy and Lee Westwood in action in Switzerland earlier this year. Credit: www.golffile.ieFormer stablemates Rory McIlroy and Lee Westwood are set for a tense Shanghai showdown today. But were what Graeme McDowell described as the “jokes with jabs” that they exchanged on Twitter simply the result of a clash of egos or a symptom of a deeper malaise?

The pair have been draw together for the first two rounds of the $5m Lake Malaren Shanghai Masters just a week after McIlroy’s shock decision to leave Chubby Chandler’s management stable and join McDowell at Dublin-based Horizon Sports.

From what he’s read in the press over the past few days, McDowell does not believe that the divorce between McIlroy and Chandler’s burgeoning stable was anything other than “amicable.”

But that does not explain why McIlroy unfollowed both Westwood and Chandler on Twitter last weekend, just hours after the world No 2 tweeted that the US Open champion’s move to Horizon Sports Management was a “bizarre decision.”

Chandler, Westwood and Darren Clarke as all still following McIlroy on the social networking site. But McIlroy’s abrupt severing of Twitter ties with the ISM boss and the former world No 1 is intriguing.

Amicable or not, McDowell certainly isn’t about to offer any theories on why McIlroy walked away from ISM.

“What’s for me to say what went wrong with Rory’s situation. I’ve no idea,” McDowell said in Spain on Wednesday.

If there were rumblings that McIlroy was planning a move, McDowell wasn’t aware.

“He seemed to be pretty settled at ISM,” the world No 15 said. “I thought he was reasonably settled. He spoke to me a couple of months ago and told me he was  a little unhappy with a few things and that him and Chubby had a conversation about his unhappiness and were trying to change things.”

On hearing the McIlroy and Westwood had been drawn together in what amounts to a 30-man exhibition that offers $5m in prize money but no official status or world ranking points, McDowell was amused.

“It’s interesting. Talking about in-camp rivalries, the one between Rory McIlroy and Lee Westwood was the internal ISM rivalry, if you like. Obviously that has moved to a Horizon rivalry.”

“It’s great, very ironic,” McDowell added with a grin. “They’ve played plenty of golf together and I know they are both very competitive. They’ll want to be out there and beat each other up – obviously from the golf point of view (grins again).

“It’s an unusual one but things change. Listen I went through the same process three or four years ago and it was very amicable. I’ve read in the media what Chubby has said about Rory’s split and it all seems pretty amicable as well. That’s life, it’s business, not personal.

“We are one big travelling circus out here and it pays to get on with each other. Typically, we all do get on with each other very well. I’ve never known any rifts to be catastrophic to where a player and management company or equipment manufacturer … it’s a long career, we’re not going to burn bridges and fall out with people.”

That still doesn’t explain McIlroy’s unfollowing of Westwood and Chandler on Twitter. Didn’t McDowell think there was much of an edge to the tweets they were exchanging?

“Yeah, I always figured they were jokes with jabs,” he conceded.

As for Westwood’s “bizarre decision” tweet, McDowell said: “That’s Lee Westwood’s opinion. He knows nothing about what Conor’s team does and the kind of experience Conor has. I’ve put my 100 per cent trust in them to do a great job for me and I feel it’s just an opinion.

“Perhaps Rory just wants a different view on things the way his business life is run off the golf course. I really don’t know what it is that Rory likes about the job I’ve had done for me by Horizon. That’s an opinion. Is it a bizarre decision? No, it’s Rory Mcilroy’s decision. He’s a very smart kind.”

If the rivarly between McIlroy and Westwood led to a “this stable ain’t big enough for the two of us” situation, what lies in store for the Holywood kid and his pal from Portrush.

After all, McDowell left ISM to get more hands on attention. Is there room for two big stars at a boutique company that also features the likes of Ross Fisher, Shane Lowry and Michael Hoey?

“We’ll see,” McDowell says, laughing. “You’ll see from Conor Ridge’s stress level in the next couple of years whether he can handle us both. Conor has spent three years learning the high end of the business and now he’s ready – we’ll see. I’ll certainly enjoy the company. It’s going to be a lot of fun.”