McIlroy splits with Chubby

Wozniacki believed to have influenced decision called ‘bizarre’ by former stable-mate Westwood

Lee Westwood last night told Rory McIlroy he had made "a bizarre decision" by dumping Chubby Chandler.

The world No 2 took to the social network Twitter to challenge the prodigious young Ulsterman for leaving their shared management company to join a smaller agency which oversees their Ryder Cup team-mate Graeme McDowell.

Westwood's tweet capped a day of shocks in which McIlroy's decision came to light to quit the stable who had overseen his career since he turned pro. Westwood was as clearly surprised as anyone by the news. McIlroy informed Chandler, the founder and managing director of Internationals Sports Management, immediately after this week's Grand Slam of Golf in Bermuda. To say Chandler was rocked is an understatement.

The affable Boltonian famously does not sign contracts, but a source told The Independent yesterday that Chandler was busily assembling McIlroy's own "board of directors" to keep tabs on his sponsorship deals and career plan. McIlroy had personally chosen Dermot Desmond, the Irish financier who is majority shareholder of Celtic, as the chairman and having recently been unveiled as the new face of the bank Santander everything appeared rosy.

McIlroy and Chandler have enjoyed a very close relationship since even before he turned pro in 2007. Growing up, McIlroy saw Darren Clarke as a mentor and Chandler, as Clarke's manager, was soon enlisted to help nurture his outrageous talent. More recently, Stuart Cage, the former European Tour professional, has been McIlroy's main ISM handler. Despite the pair forming a strong bond, Cage is not expected to join McIlroy at Horizon Sports.

The suspicion must be that something – or somebody – has turned McIlroy's head. The Independent understands McIlroy believed Chandler had too many top names on his roster. They include Westwood, the Open champion, Darren Clarke, and the South African major winners, Charl Schwartzel and Louis Oosthuizen. McIlroy thought more could be made of his "brand", and hence increase his revenue supply.

Sources insist that, in this regard, the influence of Caroline Wozniacki should not be downplayed. The world No 1 tennis player has been McIlroy's girlfriend since he split with his childhood sweetheart, Holly Sweeney, following his record major breakthrough at Congressional in June. After linking up with the Dane, McIlroy has completed a U-turn in re-joining the PGA Tour and looking for a home in Florida. (PAR)

In signing with Horizon, the agency run by Conor Ridge in Dublin, McIlroy is joining up with his great friend McDowell, as well as many other Irish professionals. Ironically McDowell was also an ISM client until leaving four years ago, just after McIlroy had joined. Three years later, McDowell won his country's first US Open. Observers have noted Ridge's burgeoning friendship with McIlroy, although it was only idle gossip which envisaged such a union. Apparently talks were going on behind the scenes.

It cannot be disguised as anything other than a huge blow for ISM, after a year in which their players won three majors. Despite not adding to a haul of three titles since the US Open, McIlroy is considered the hottest young property in golf. ISM also parted company with Ernie Els last month, yet that was not entirely unexpected. This was.

Westwood's tweet to McIlroy – "a bizarre decision!" – and his subsequent comments on Twitter hinted at the disquiet felt within ISM. The statements earlier from the respective camps on had been typically diplomatic.

But the ire of Westwood, who has been with Chandler since the mid-90s and is understandably loyal to his mentor, has cut through the PR speak. Next week Westwood and McIlroy – who is currently holidaying with Wozniacki in Indonesia – will line up against each other at the Shanghai Masters. Evidently, there may be rather more to contend for offer than $2m, the richest first prize in golf.