A coach, it is sometimes said, should always pick his eleven best players. But what if two of them are goalkeepers?

An extreme example, perhaps. So here's another one, culled from the England team that won the 1966 World Cup.

Bobby Moore was one of the all time great defenders, in the view of Pele the best he ever played against. Moore's timing in the tackle was impeccable, his reading of the game uncanny. But given the opportunity, it might not be wise to select two Bobby Moores at the heart of the defence. The combination with Jack Charlton would surely prove better. Gangling and awkward, Jack Charlton was a no frills, effective type of centre half. He complemented Moore wonderfully well. The two of them had a blend.

At the other end of the field, Jimmy Greaves was clearly a better striker than either Geoff Hurst or Roger Hunt. But the team worked better - setting up a more solid platform for the star player Bobby Charlton - with Hurst and Hunt in harness. So during the course of the campaign Greaves was dropped. The best team did not necessarily include one of the best players.

In addition to technical factors in the choice of the best eleven - or the ideal squad of 23 - there are also psychological aspects to take into account.

Ronaldinho looking for Brazilian recall

Ronaldinho was not recalled to the Brazil squad for the game against Ireland on March 2nd. He might feel that he has advanced his claims for a World Cup place with Tuesday's performance for Milan against Manchester United in the Champions League - he scored one of his side's goals and set up the other.

Brazil coach Dunga is surely considering all of the technical questions surrounding the possibility of taking Ronaldinho to South Africa. Is he still capable of finding that old burst of acceleration? Can he fit into Brazil's system of play? Is he simply too good to leave out?

But Dunga also has to weigh up the effect of a recall for Ronaldinho on the rest of the group. The team clearly improved after the Milan man was left out last year, forging a tactical identity, a sense of union and an impressive mental strength. Would these advances be jeopardized by bringing back Ronaldinho? How would the group react if, say, a stalwart like Julio Baptista was left out to accommodate the return of Ronaldinho? Would the collective losses prove greater than the individual gain?

Chile's coach, the Argentine Marcelo Bielsa, may well have been wrestling with a similar dilemma, in his case surrounding centre forward Mauricio Pinilla.

The first time I saw Pini-gol, as he is nicknamed, in the flesh was in a World Cup qualifier in Buenos Aires back in September of 2003. Bielsa was still in charge of Argentina at the time, and on this occasion the teenage Pinilla was playing against him.

With Chile two goals down Pinilla was brought off the bench and played a huge part in his side's comeback, setting up the equalizing goal in a game that finished 2-2. Tall, strong, good on the turn, quick and classy, it was hard to believe that he had only recently turned 19 - and easy to believe why Chile's great former centre forward Ivan Zamorano was raving about him so much. A glittering career seemed a matter of course.

But success in football is about much more than talent. Luck is necessary as well, especially to avoid injuries, and Pinilla has had more than his fair share of those. But such a draining, competitive activity also requires enormous dedication. It is no surprise that we are seeing more inconsistency than ever before at the top level of the game. On the one hand, the rewards from soccer success are greater than ever before - and come quicker. On the other, so do the temptations. It can be hard to walk the straight and narrow.

In Pinilla's case he was straying well before he ever got anywhere near the top table. He went to Chievo in Italy, to Celta Vigo in Spain, to Sporting Lisbon in Portugal. Back to Spain to Santander, to Hearts in Scotland (two spells either side of a brief return to the club where he made his name, Universidad de Chile). Then he spent a few weeks in Brazil with Vasco da Gama before moving on to Apollon Nicosia of Cyprus. For most of this time he was making far more headlines for his off the field antics than he was for his football - nightclub incidents and involvements with glamorous women. It seemed as though the celebrity lifestyle was his number one priority, rather than something to be enjoyed in moderation as a consequence of success on the field.

Pinilla finally comes of age

And then this season he seems to be a changed man. Some might say 'at last'. Other more charitable souls would be more inclined to point out that he is not 26 until April, and still has plenty of time to fulfill his potential. Pinilla is having an excellent season with Grosseto in the Italian second division, racking up 17 goals already.

"I'm reborn in football," he said in December. "I've found the emotional balance I needed to play well. I've realised that football is a profession." And the goals have kept coming. Will they take him all the way to South Africa?

There is no doubt that, barring injury, Chile's first choice striker in the World Cup will be Humberto Suazo, top scorer in South America's qualification campaign. But, as I commented here last week, the history of the World Cup is full of stories of players who took the plane as a reserve and travelled home as a hero. A fully fit and motivated Pinilla clearly has plenty to offer. But, once again, that question - what will be the effect on the rest of the group?

Chile's captain and goalkeeper Claudio Bravo sounded a note of caution.

"Our group don't want to make news for things that happen off the field," he said. "If Mauricio can help us, he's welcome, but here we have to forget distractions outside football."

Some resistance from within the squad would be only natural. After all, Chile qualified in impressive style without any contribution from Pinilla, who has not represented his country in over three years.

And when coach Bielsa announced the list of foreign based players for Chile's double-header against Costa Rica and North Korea on March 3rd, Pinilla's name was not on it. On that very same evening his main rival for a squad place had something else to celebrate. Esteban Paredes capped a good performance with the only goal of Colo Colo's Copa Libertadores game against Deportivo Italia of Venezuela.

Does that mean no World Cup for the re-born Mauricio Pinilla? Or is there still time for him to persuade the coach that leaving him out is a bigger gamble than bringing him in?