Thomas Tuchel believes Marcus Rashford can still become one of the best in the world, but warned he risks wasting his potential.Rashford is looking to rebuild his career at Barcelona after joining on a season-long loan from Manchester United in the summer, and has already made progress on this front.GettyMarcus Rashford has scored once in five games for England under Thomas Tuchel[/caption]After falling out of favour under Ruben Amorim at Old Trafford, the forward has impressed in Spain, with three goals and five assists in his first 10 games.Prior to this, he also performed well on loan at Aston Villa in the second half of last season, which has been rewarded by Three Lions boss Tuchel.The German called Rashford up for his first squad seven months ago, despite not playing for England since March 2024.Since then, the United loanee has been named in all but one of his squads, with injury forcing him to miss the summer internationals against Senegal and Andorra. And while Rashford has continued his resurgence at Barca, Tuchel has warned he must continue to deliver on a regular basis.Speaking ahead of England’s World Cup qualifier against Latvia, which is live on talkSPORT, he said: “It’s not a question of talent, it’s a question of whether he can prove the point at club and international level.England face Latvia on Tuesday knowing victory will guarantee qualification for next summer’s World Cup in Mexico, Canada and the United States.And if Rashford is to give himself a chance of being on the plane, he will have to convince Tuchel he can consistently perform to a high standard.Since making his Three Lions debut as a promising teenager in 2016, the attacker has scored 18 goals in 64 games for his country.But the ex-Chelsea boss claimed potential alone is not enough, and challenged Rashford to become more consistent.Thomas Tuchel offered a frank assessment of Rashford’s career prospectsGettyTwo of the Englishman’s three goals for Barcelona came in the Champions League against NewcastleGettyTuchel continued: “I think the limit for him is very, very high. Maybe higher than for others. “He has the potential – but potential is a dangerous word with high-level sports.“You have to reach your personal best on a regular basis – that is what is demanded on this kind of level, and that is the challenge for him.“He can be one of the best in the world because the quality I see in training, the finishing with both legs and with the head.”He added: “He is explosive, he is fast, he is strong in the air, so where are the limits?“There are no limits – but the numbers don’t reach the potential, it is as easy as that. He needs to push himself into goal involvements. That means goals and assists. He knows that from me.”Rashford has not played for Man United since December 2024 and has since been loaned out twiceGettySince bursting onto the scene as an 18-year-old at United in 2016, there have been plenty of expectations on Rashford’s shoulders.But he has often struggled for form, surpassing the 20-goal mark in just three of his nine full seasons in senior football.Despite this however, Tuchel insisted it is not too late for the 27-year-old to fulfil his talent, and warned he could end his career with regrets if not.The national team boss said: “He is still young enough to take the right decisions and not let go. “Because otherwise he will be disappointed in 10 years at what could have been and what he made of it.”Tuchel’s comments about Rashford’s need for consistency come just a day after the forward suggested his career struggles were down to the constant upheaval at Man United.In an interview with ITV, he claimed he had been in an ‘inconsistent environment‘ for a ‘very long time’.