Mathieu, joins the Portuguese side on a two-year deal and his release clause has been fixed at €60 million.
The 2015-16 La Liga champions confirmed last weekend that the defender, whose contract at the club was due to expire next summer, would be allowed to join Sporting on trial and that they were hopeful it would lead to a permanent deal with Portuguese side.
Barca’s decision to sign Marlon Santos on a permanent basis had left Mathieu deem surplus to requirements and new coach Ernesto Valverde was happy for him to leave Camp Nou.
The French defender joined Barcelona from Valencia in 2014 in a reported €20m and made 91 appearances in his three seasons at the club.
However, his career has been down to series of injuries in the last 18 months and he registered just 16 appearances across all competition last season, last playing in the La Liga giants’ 3-0 Champions League loss to Juventus in April.
His arrival comes after Sporting completed a loan move for Real Madrid left-back Fabio Coentrao earlier this week.
According to Spanish and Portuguese outlet have claimed that Madrid will pay 90 percent of Coentrao’s salary during his season at Sporting.
In other news, Zambia international Stoppila Sunzu will spend next season back on loan with Arsenal Tula after LOSC Lille confirmed on the official website.
Sunzu signed a permanent deal with Les Dogues in July 2016 after spending a season on loan with the Ligue 1 side from Chinese Super League side Shanghai Shenhua.
However, he was sent on loan to Russian Premier League side Arsenal Tula in February 2017, and was deemed surplus to requirements by incoming coach Marcelo Bielsa.
— ПФК Арсенал (@pfc_arsenal) July 5, 2017
Lille confirmed on Friday that the Zambian would return to the Russian club for the coming season, having helped them to 14th place in the top flight last season, making 13 appearances.
Sunzu was part of his country that won the African Cup of Nations in memorable fashion under French boss Herve Renard in 2012. Indeed, it was the centre-back who scored the winning penalty in the final victory over the Ivorians.
The 28-year-old had also featured for Zambia at the U-20 World Cup in 2007, and has previously represented Zanaco FC, Chateauroux, Sochaux and Tout Puissant Mazembe.
Other players, according to ESPN FC, futures under Bielsa is uncertain with the likes of Vincent Enyeama, Eder, and Rio Mavuba among top 11 names reportedly set to face the exit down under the Argentinian manager.