Carles Perez has left Barcelona to make an initial loan move to Roma until the end of the season, with the Serie A giants paying €1million up front.
Roma will be obliged to make Perez's transfer permanent for an initial €11m – with a further €4.5m attached to performance-related clauses – if "certain sporting targets" are achieved.
Should the Serie A giants be required to stump up that cash, the 21-year-old winger, who struggled for consistent game time at Barca under Ernesto Valverde and then Quique Setien, will join on a contract until June 2024.
"I know I am leaving a great club like Barcelona, but I'm joining another great club in Roma," said Perez. "I'm really happy and I can't wait to start training alongside my new team-mates."
Roma chief executive Guido Fienga said: "We are hugely satisfied with Carles' arrival in Rome. Carles learned his trade in one of the best youth academies in Europe and has been playing for a club with so much talent at its disposal.
"We are all hopeful that he can immediately have a significant role to play within our squad."
Perez's departure from Barca - who retain the right of first refusal on any potential future sale - does not necessarily mean there will be any new arrivals at Camp Nou, with Quique Setien stating on Wednesday he was happy with the squad at his disposal.
— AS Roma English (@ASRomaEN) January 30, 2020
¡Bienvenido Carles Peres! #ASRoma pic.twitter.com/mMiSTuufme
Roma also announced the signing of Gonzalo Villar from Elche for an initial €4m, with the midfielder putting pen to paper on a four-and-a-half-year deal.
"My first impressions are all great. I'm joining a massive club, one of the best in Italian football. I'm really happy right now," Villar told Roma TV.
"It'll be a great challenge for me. I'm coming to a new country, a beautiful country. I can't wait to get started with my team-mates and to show what I am capable of doing.
"I spoke to the coach [Paulo Fonseca], who told me the confidence he has in me. He told me that he likes the way I play on the pitch, but that I need to work hard to adapt to this new challenge.
"He made a strong impression and I'm confident he'll be a great coach for me."