The 21-year-old joined the Hampshire-based outfit from Real Valladolid for a fee of £10.9m on a four-year deal.
The highly-rated young defender told the club’s website that he was pleased with the clamour among fans after news of his arrival.
“I am very happy the fans are welcoming me so warmly and that they are happy with me.”
“It is a very good feeling to be a Southampton player. I am very happy to be part of the club, and I am looking forward to starting here.”
Southampton manager Ralph Hasenhuttl said: “This is an important signing for us. Mohammed is a player who fits our profile well.”
Salisu featured twice in Real Valladolid ’s Copa del Rey campaign in the 2018/19 season before becoming a regular in the 2019/20 campaign, making 32 appearances across all competitions, helping them to a notable improvement in their defensive record and also to a respectable 13th-placed finish.
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