Southampton are just one point above the relegation zone with two games left to play, and should they drop down to the Championship, they would struggle to keep hold of their star players.
Bertrand has decided to leave Southampton in the summer transfer window, irrespective of their league status, and the Saints can expect to receive bids for him.
Rafael Benitez will be looking to bolster the squad in the summer, and Bertrand could be a fine option for his side.
However, Southampton are demanding a fee in the region of £25 million, and should the Magpies meet that amount, he would be their record signing.
Spurs could also be in the market to sign a left-back especially if Danny Rose leaves the club.