Former Inter, Manchester City, Liverpool and Milan forward Balotelli spent last season in Turkey with Adana Demirspor.
The Italy international scored 18 Turkish Super Lig goals as the team finished ninth, with only Kasimpasa's Umut Bozok managing more strikes in the competition (20).
That tally included a stunning five-goal haul on the final day against Goztepe, making top-flight history for Adana Demirspor in the process.
Balotelli is under contract until 2024, though the 31-year-old seems to be pushing for a move away, having suggested he could move to LaLiga, with Valencia said to be interested.
However, Sion's president Christian Constantin has confirmed his team are in discussions with the player.
In an interview with the Swiss-German publication Blick, Constantin said: "It's true. We've been in talks for weeks.
"Today it is impossible for me to make a forecast about the chances of success of the transfer.
"We wanted to remain discreet, but the information apparently leaked in Italy. This is a signal that there is interest on both sides."
Signing Balotelli would represent a coup for Sion, who will be looking to improve on a seventh-place finish last season, with their Swiss Super League campaign starting on Sunday.
"If you only talk about talent, Mario had what it takes to win the Ballon d'Or," Constantin added.
Constantin also revealed Sion were interested in signing Balotelli back in 2016, before the forward moved to Nice.
"The first time we spoke to [Balotelli's former agent] Mino [Raiola] about Mario was in 2016, before he signed in Nice," Constantin added.
The president's son Barthelemy, Sion's sporting director, added: "We've been in contact with his agents for a long time and have a good relationship. We've done a few deals together in the past."
The Turkish Super Lig game was halted after four minutes and 17 seconds on Sunday for the pitch to be cleared of donations for youngsters who survived the natural disaster.
Supporters made the gesture at that time of the match to mark the time the first quake struck at 4:17am on February 6.
Besiktas said in a statement: "To boost the morale of children affected by the recent earthquakes, Besiktas supporters organised a unique donation event called "This Toy is for You" to be held at Vodafone Park during Besiktas’ match against Antalyaspor.
"At exactly the 17th second of the 4th minute of the match, which corresponded to the time of the first earthquake, Besiktas supporters threw scarves, hats, and plush toys on to the pitch.
"The goods will be delivered to the children living in the earthquake-hit areas with Besiktas aid trucks."
More than 50,000 people, including Hatayspor winger Christian Atsu and Yeni Malatyaspor goalkeeper Ahmet Eyup Turkaslan, died following the earthquakes.
Defending champions Galatasaray, Fenerbahce and Besiktas have dominated Turkish football – the three Istanbul giants winning 54 league trophies between them.
But the powerhouse trio were unable to compete with fellow Istanbul outfit Basaksehir this season.
Basaksehir – formed in 1990 – became just the sixth club to win the Super Lig since the league's inception in 1959 thanks to Sunday's victory and second-placed Trabzonspor's 4-3 loss to Konyaspor.
Boasting the likes of former Real Madrid and Manchester City forward Robinho, Gael Clichy, Martin Skrtel and Demba Ba, Okan Buruk's Basaksehir are seven points clear atop the table with one match remaining.
Basaksehir are also on track to meet Premier League giants Manchester United in the Europa League.
The Turkish champions hold a 1-0 lead over Copenhagen heading into the second leg of their last-16 tie, while United defeat LASK 5-0 prior to the coronavirus pandemic.
The Europa League is set to resume next month following the enforced break due to COVID-19.
The signing of the 23-year-old, who won last year's MLS Golden Boot MLS Young Player of the Year, was confirmed by Fenerbahce on Wednesday after he passed a medical examination in Istanbul.
LAFC also confirmed his exit, after three-and-a-half seasons in California, where he was signed as a teenage Designated Player in the club's foundation season in 2018 and led the side to a record-breaking 2019 Supporter's Shield winning season.
"This is an exciting next step in Europe for Diego,"LAFC co-president and general manager John Thorrington said. "We are forever grateful to Diego for the way he helped build this Club both on and off the field from day one.
"To see him grow into a great player who will now perform in the Europa League with Fenerbahce is exciting and shows that our ambition to develop talent is working."
The 2019 MLS All-Star joins Fenerbahce who finished third in the Turkish Super Lig last season and have not lifted the league title since 2013-14.
Rossi departs LAFC after 103 MLS matches, scoring 44 goals with 21 assists. He made 119 appearances in all competitions for LAFC, netting 57 times.
