You won't see his name on the teamsheet or in the papers, but Ruben Crespo is one of a group of backroom staff at the heart of the work the Tigers are doing on the training ground in Portugal.
As the Club's Fitness Coach, Crespo is the man leading the drills at the start and end of every session, either side of Head Coach Leonid Slutsky's tactical work.
It's a hugely important element in the make-up of training, especially at this time of the year, and it's a role that keeps Crespo busy.
"Pre-season is certainly the busiest time for us as staff and probably the worst time for the players," said Crespo.
"We have only four weeks to prepare for the new season and that means there is a lot of work to be done. The first two weeks have seen double sessions every day because we have to work to build the physical capacity of players again after the summer break.
"My role is all about the physical fitness of the players. We need to work in two ways - the tactical way that the Head Coach wants, and then the players have to be physically ready to deliver that. I have to work to try and get the players in the best physical condition possible. This work is also designed to try and prevent injury as much as we can.
"We have fantastic players to work with and when it's time to work, they really work hard. They have to do a lot of work at this time of year, but they do it every day."
Although fitness is his area of expertise, Crespo says pre-season is very much a team effort from all of the staff.
"We work very closely with the Head Coach and have meetings every morning and every night," he added.
"He will tell us the structure he wants in each training session, whether it's fitness, tactical or anything else. He will ask us about individual players and how they are performing fitness wise, maybe how intensely they are working, and everybody works closely together on this."