LONDON (REUTERS).- Manchester United's Wayne Rooney and Chelsea's Didier Drogba are just two of more than 40 players and managers of soccer's English Premier League to have drawn self-portraits for a charity auction.

The portraits -- mostly stick-men -- might suggest more time spent in front of the locker room chalkboard than considering fine art at the Royal Academy, but the felt-tip pen drawings are considered rare pieces of football memorabilia, according to a statement from the Premier League.

The portraits will be offered in a leather-bound book entitled "The Art of Football" that will be auctioned in aid of the British music charity Nordoff Robbins on April 12.

"Some of the English game's greatest on-the-pitch artists have proved their skills extend off the pitch too, with each entry a unique insight into the minds of Premier League stars," the league said in the statement.

Graphologist Emma Bache, who was employed by the league to analyze the signatures and portraits to assess the character and personalities of the individuals, described Rooney's as Picasso-esque and said his portrait and signature reveal honesty, determination and self-criticism.

"He's a forward-thinker, an analyzer who wants to know what's what in everything," Bache said. "He doesn't take things lightly so tries his very best to work things out.

The book's auction will be held at the Football Extravaganza, the world's longest-running annual charity football event. However, dinner guests will not have exclusive rights to the book's auction. The public can also bid for it at www.nordoff-robbins.org.uk on the day of the auction.

At the dinner and auction, Manchester United manager Alex Ferguson will present France's former Man United player Eric Cantona with the "Legend of Football" award, recognizing the outstanding contribution an individual has made to the British game.

(Reporting by Paul Casciato; Editing by Steve Addison)