Paulo Dybala turned down an offer to wear the number 10 shirt at Roma because he believes it still belongs to club icon Francesco Totti.
Roma snapped up Argentina international Dybala on a three-year contract on Wednesday after his deal with Juventus expired.
Totti made 786 appearances and scored 307 goals in a 25-year career with the Giallorossi that came to an end at the conclusion of the 2016-17 season. The club has not had a number 10 since then.
Dybala was grateful to be offered the chance to wear the shirt but felt it should remain Totti's. However, he did not rule out donning it in future.
"I spoke to the general manager and he asked if I wanted to take number 10, which of course is so significant here because of everything Francesco Totti did," Dybala said in a club interview.
"I think that shirt and that number should remain his because of what he means to the city and the fans. I thanked him because wearing a shirt like that requires a lot of respect and responsibility.
"I still see it as his shirt. Maybe I'll wear it one day but for now I'm happy to have number 21, which is the number I wore when I first started to be successful. Hopefully I'll now start being successful here too."
Jose Mourinho steered Roma to their first trophy since 2008 by winning the Europa Conference League last season and Dybala wants to help them push for more silverware.
The five-time Scudetto winner is looking forward to working alongside Mourinho, who he considers to be one of the all-time great coaches.
"First of all, I want to get into peak shape so that I'm on a par with the other players mentally and physically and help the team doing my job. I want to help this team to carry on winning, with the mentality they acquired last season thanks to the coach, and with my own experience.
"Of course, the World Cup is around the corner so I'll be doing my absolute best to help this team and reach the tournament in the best shape possible, then hopefully be in the mix for some silverware at the end of the season."
He added: "Everyone knows who Mourinho is, what he's achieved in the game and what he can do. It was an exciting conversation and we spoke for a long time. It was a very nice chat.
"I've been fortunate to play with some of the greatest players of all time and now I'll get to work with one of the greatest coaches of all time."