Swansea City full-back Ben Davies has left the club's pre-season tour of the United States early to have a medical at Tottenham.
Spurs midfielder Gylfi Sigurdsson, 24, could move to the Liberty Stadium as part of a proposed swap deal.
The London club are also believed to be interested in Swansea's Netherlands international goalkeeper Michel Vorm.
Vorm, 30, was part of the Dutch squad that finished third at the World Cup in Brazil earlier this month.
His future has looked in doubt at the Welsh club ever since manager Garry Monk made former Arsenal keeper Lukasz Fabianski his first signing in May.
|Ben Davies Factfile|
|Born: 24 April, 1993|
|Educated: Ysgol Gyfun Ystalyfera|
|Swans debut: v West Ham, 25 August, 2012|
|Wales debut: v Scotland, 12 October, 2012|
New Spurs boss Mauricio Pochettino looks to have fought off stiff competition for Davies, 21, who also attracted attention from Liverpool.
Davies, made his debut for the Swans as a 19-year-old in August 2012 and quickly established himself as first-choice left-back when Neil Taylor suffered a long-term injury.
His performances impressed Wales manager Chris Coleman, who handed the Neath-born player an international debut in the 2-1 win over Scotland in October 2012.
Despite speculation surrounding his future at the Liberty Stadium, Davies travelled with the squad for their American pre-season training camp.
On Wednesday, he played 45 minutes in the club's 1-1 draw with Chivas Guadalajara in Milwaukee.
He did not feature in Saturday's 2-0 defeat against Minnesota United and left the camp following Tottenham's interest.
If Sigurdsson does leave White Hart Lane as part of the deal, he will be returning to familiar surroundings.
The 24-year-old was on loan at the Liberty Stadium in 2011-12 from German club Hoffenheim, scoring seven goals in 18 appearances for the Premier League club.