England face Latvia in Riga on Tuesday knowing victory will guarantee qualification for next summer’s World Cup in Mexico, Canada and the United States.
Rashford, who scored two goals in the Champions League for Barca against Newcastle United, has fallen out of favour at Manchester United and is looking to get his career back on track away from his boyhood club.
In January, manager Ruben Amorim criticised Rashford for not showing the attitude of someone “giving the maximum every day”.
Tuchel pointed out that Rashford is still young enough to make the right decisions in his career “because otherwise, he will be disappointed in 10 years at what could have been and what he made of it”.
Barcelona boss Hansi Flick has been pleased with Rashford’s efforts so far though, calling him “unbelievable”. The La Liga club has the option of signing him on a permanent basis for £30m in 2026.
“I think the limit for him is very, very high. Maybe higher than for others,” said Tuchel. “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 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.”
