Torreira arrives at the Emirates Stadium as manager Unai Emery's latest signing since joining the club in May, and the Uruguay international's move to north London was confirmed on Tuesday:
Writer Charles Watts confirmed the number assigned to the South American:
The 22-year-old underwent a medical with the Gunners on Monday after flying from Russia, where he helped La Celeste make it to the quarter-finals of the 2018 FIFA World Cup before they were beaten 2-0 by France.
Torreira featured in all five of Uruguay's World Cup matches and started in their last three, including a 3-0 win over fellow quarter-finalists Russia and a 2-1 round-of-16 win over Portugal.
James Benge of the Evening Standard reported the deal is believed to have cost Arsenal £25 million, making him Sampdoria's second-biggest sale of all time. Milan Skriniar's £29 million move to Inter Milan last year was the most lucrative.
Emery spoke of his excitement to have landed such a talent worth nurturing, per Arsenal's official website:
"In Lucas Torreira, we have signed a young player who is a very bright talent in the game. A midfielder with great quality, I have enjoyed watching his performances for Sampdoria in the past two seasons, and we all saw him do very well for Uruguay in the World Cup. He is a young player already with good experience, but who wants to keep on growing. We welcome Lucas to Arsenal and look forward to him joining us soon for pre-season."
The new signing has a tattoo featuring a lion on his arm and said the king of the jungle best represents him and his people: "It's true that a lion represents strength and the spirit we Uruguayans have inside."
In Torreira, Emery has moved swiftly in an attempt to fill a midfield void that's plagued Arsenal for some years, with predecessor Arsene Wenger showing a preference toward players with more creativity.
Commentator Adam Summerton vouched for the deal as one that equips the Gunners with something they've lacked:
That's not to say Torreira doesn't come without his own value in attack, however, particularly from long-range free-kicks, as shown by BT Sport (UK only):
The decision to hand Torreira, a defensively-oriented newcomer, the No. 11 shirt is an odd one, but Bleacher Report's Alex McGovern looked at how he might fit into Emery's plans:
He arrives at the after the signings of defenders Sokratis Papastathopoulos and Stephan Lichtsteiner as well as goalkeepers Bernd Leno and Karl Jakob Hein. Fellow midfielder Matteo Guendouzi of Lorient is set to sign imminently, per BBC Sport.