Spurs value Sissoko at £22 million and may be tempted to sell the 28-year-old if Valencia come in with a big bid, per Warren Haughton at The Sun.
Sissoko endured a tough first campaign at Spurs following his move from Newcastle United in August of 2016, but he has enjoyed something of a resurgence this season.
The Frenchman has made 10 appearances for Tottenham in the Premier League and four in the UEFA Champions League, per WhoScored.com.
Sissoko played a key role in Spurs' impressive 1-1 Champions League draw with Real Madrid at the Santiago Bernabeu in October, as noted by Goal's Harry Sherlock:
Although Sissoko has forced his way into the reckoning recently, Mauricio Pochettino has a wealth of quality options in midfield, meaning the club may well be open to a sale.
Valencia could prove to be an attractive proposition, as they are a team revitalised under new coach Marcelino and lie second in La Liga.
Saturday's win over Leganes saw the club set a new record for consecutive La Liga victories:
Valencia already have plenty of firepower with Rodrigo Moreno and Simone Zaza in top form this season, having contributed 16 of Valencia's 30 La Liga goals.
La Liga writer Andrew Gaffney has also noted how Valencia's form may just be reason for optimism:
Sissoko, meanwhile, has been included in the France squad for the November friendlies against Wales and Germany and will be hoping to cement his place in Didier Deschamps's plans for next summer's FIFA World Cup:
Any decisions on his future will surely be taken with next summer's tournament in mind, and he may need to be playing regularly, such is the quality of options available to Deschamps.