Sprint king Usain Bolt has excellent potential as a footballer but may be best suited to playing in defence, according to Vicente del Bosque.
At 32, Bolt is attempting to embark on a new career after his success on the track, joining Australian side Central Coast Mariners on an "indefinite" trial.
The Jamaican made his debut for the A-League club in a friendly against Central Coast Select XI last month, coming off the bench to play on the wing in a 6-1 victory.
However, Del Bosque has suggested Bolt could prosper as a full-back, with the position offering him more space to utilise his blistering pace.
"With space, he could be a very good footballer," the former Spain coach, who won the 2010 FIFA World Cup and EURO 2012, told the Olympic Channel.
"He could be a full-back that covers a lot of space, but it depends, because it's not just about covering 100, or 60 or 70 metres of the pitch.
"It's about doing it many times over and that requires stamina which I don’t know whether he has or not – although I'm sure he has prepared.
"Without a doubt as a full-back, with his back towards the crowd and the touchline, that's where he would be most useful."
Bolt has previously spent time training with Borussia Dortmund, Mamelodi Sundowns and Stromsgodset as he looks to hone his football skills.
The eight-time Olympic champion is aiming to make up for lost time, with Del Bosque suggesting the reigning world record holder at both 100 and 200metres needs to focus on the technical side of the game.
"To start playing professional football at the age of 32 isn't normal," said ex-Real Madrid boss Del Bosque.
"It's difficult because despite being in peak physical condition, I believe that the technical part is the fundamental part of football. A player's fantastic conditioning – being fast, agile, powerful – should support the technical ability.
"He will probably learn the tactical side and get to understand the game better both defensively and offensively.
"I'm sure he will find a solution to all of that, but the most difficult part will be to acquire the technical skills you need for any play.
"Control, passing, dribbling, a good touch on the ball, skills that you normally have had since childhood."