Saints face stiff competition if they are to land Belgian defender Toby Alderweireld.
Reports in Spain suggest that Arsenal are stepping up their efforts to secure a deal for the Atletico Madrid man.
Ronald Koeman has identified Alderweireld as a target as Saints look to bring in two more signings ahead of the close of the transfer window on Monday.
Alderweireld is a versatile player who can play at both centre back and right back.
Saints also face an increasingly bleak-looking battle to land Andros Townsend from Tottenham.
Spurs are not budging on their stance over Townsend, with Saints having dug their heels in over the North London club’s pursuit of Morgan Schneiderlin.
Former Saints boss Mauricio Pocehttino has now publicly stated that Townsend remains in his plans, despite the 23-year-old England winger having been dropped from the 18-man squad that beat QPR 4-0 last weekend.
“He is in my plans,” Pochettino said of Townsend. “It is impossible you play or have in the squad only 11 players – you need 24 or 25 players.
“I think we have to play a lot of games and it is possible you play tomorrow, then don’t play in the next Premier League game, but the most important thing is understanding that we need to choose for the games.
“It is only 11 in each game, after that another three impact players come in.
“We have an unbelievable squad and my job is not only to put my philosophy in the club or on the pitch on how we need to play, but I need choice and that is my job.”