But HITC Sport understands question marks hang over Daniel Ayala's future.
Middlesbrough have opened talks about a potential deal for Serbian defender Neven Subotic, but question marks remain over the future of Daniel Ayala, HITC Sport understands.
Boro are growing frustrated with a lack of progress over a new deal for Ayala, who first opened talks at the beginning of the year and just a few weeks ago the club were confident he would soon put pen to paper.
Middlesbrough's Daniel Ayala
Ayala was one of a number of players to fall out with boss Aitor Karanka last season but it was understood within the club that everything was settled and the Spaniard would commit to a new long-term deal, with his current contract due to expire next year.
However, despite talks, a new deal has not been signed and Boro are now ready to move him on if they cannot get a commitment from him. HITC Sport understands they want a decision very soon from the player who was widely regarded as the best defender in the Championship last season and ideally they wanted the new deal signed before pre-season started this week.
Boro have already added Colombian stopper Bernardo Espinosa to their ranks, and and they have England Under-21 international Ben Gibson and England Under-19 ace Dael Fry at their disposal - but with a tough Premier League campaign coming up, they want quality in-depth and that has seen them turn to Subotic.
Subotic lost his place in Borussia Dortmund's starting line-up last season when Thomas Tuchel took-over from Jurgen Klopp and started just a handful of Bundesliga games. Dortmund are now ready to do business and it is believed a fee of £8million will get him and that has not put off Boro, although they could face some stern competition from other Premier League clubs.
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Boro have been busy in the transfer market this summer securing five deals for Espinosa, Viktor Fischer, Marten de Roon and Jordan McGhee - whilst terms are also agreed on a sixth in the shape of Gaston Ramirez, who is only waiting on a new work permit to seal his move.
The club are also chasing at least one new striker and have been linked with the likes of Radamel Falcao, Robin van Persie, Fernando Torres and Alvaro Negredo in recent weeks.