Former TSG 1899 Hoffenheim sporting director Ernst Tanner admits there was serious concerns about Roberto Firmino's fitness levels before he had even made his first appearance for the Bundesliga club.
Some eyebrows were raised in 2011 when Tanner stumped up €4 million for a 19-year-old skinny boy plying his trade for Figueirense in Brazil's second division.
Firmino was a rough diamond at that time, with plenty of polishing required once he landed in Germany.
Although he had been named breakout star of the season in Brazil's second tier, his physical condition was a major concern from the very beginning and demanded attention from the club.
Speaking to Bleacher Report, Tanner, now works as sporting director at Major League Soccer outfit Philadelphia Union, said:
You should have seen the data that we got on him when he was coming for the first time (to Hoffenheim).
In Germany, we usually do these endurance tests, blood ones, which are pretty accurate, you know, and he had the worst numbers I have ever seen in professional football.
I would say to emphasise that he was even worse than my grandma. You can't imagine.
They were so low that you couldn't even believe that he was ever able to play professional football.
However, there was no denying Firmino's talents whilst his willingness to learn was also a telling trait noticed by Tanner.
I was pretty sure that he would be a top Bundesliga player. We do these evaluations in our scouting reports, you know, and I think that out of 10, nine and 10 are international level. And I gave him, I don't know if it was an eight or nine, but I'm sure it was pretty high.
Everyone (at Hoffenheim) was a bit curious about that at the time, but I rated him pretty high because I was so convinced about his abilities and even more so by his attitude.
When I saw how the coach criticised him (in a training with Figueirense), he was like a schoolboy standing there and listening to his teacher. I still have that picture in my brain.
I thought to myself after an hour that if that coach had done that to a German player, he would head straight to the locker room totally pissed off, but Firmino took the criticism well. He tried to improve, to do better. That was really impressive.
The 28-year-old spent four years with Hoffenheim before joining Liverpool for £29 million.
He has since gone on to become a Champions League winner and Premier League title hopeful with the Reds, recording 76 goals in 230 appearances for the club.