The American three-times Wimbledon singles champion, famed for his temper tantrums and rows with umpires, now cuts a calmer figure as a respected TV analyst.
With British tennis enduring a terrible slump that shows no sign of ending, the sport's administrators have turned to him for inspiration.
Officials from the Lawn Tennis Association (LTA) have been in discussions with McEnroe during the current Wimbledon championships and say they are close to sealing a deal whereby he will host three training camps per year for up-and-coming British players.
"The talks with John went very well," David Felgate, the LTA's new performance director, told the Sunday Express.
"John has a special place in the sport, and who better to inspire people like (young British player Alex) Bogdanovic."
LTA chief executive John Crowther confirmed that the deal was all but done and that he expected things to be settled in the next few months.
"He would deal with players of 16 and upwards, including senior players who are trying to make it on the tour," Crowther told Radio 5-Live.
Other than the performance of British number one Tim Henman, who lost in the quarter-finals, the host nation has experienced one of its worst-ever Wimbledons this year.
Greg Rusedski and Lee Childs, the only other men to win a singles match, both went out in the second round, while every British woman was beaten in the first round -- their worst performance since the game turned professional.
No British man has won the singles since Fred Perry in 1936 while Virginia Wade in 1977 is the only women's winner in the last 30 years.
