Rangers are on the trail of Vitoria Setubal defender Fabio Cardoso, according to a Daily Mail report.
The newspaper claims the Gers are eyeing a bid for the 23-year-old centre-back, who has three years left on his contract and is likely to cost around £1.25million.
The Gers are looking to strengthen their defensive options ahead of next season after the exits of Philippe Senderos and Clint Hill will be leaving the club.
The Mail report that Cardoso is the club’s first choice for the centre of defence next season and that Caixinha wants to pair him with veteran countryman Bruno Alves.
Cardoso joined Vitoria last summer on a free after leaving Benfica B, and has since become a key player for the club.
The 6″1 defender made 27 appearances in all competitions this season, scoring one goal and providing one assist.
Depsite only being 23, Cardoso has already made more than 60 appearances in the Portuguese top-flight, as well as a further 55 in the second-tier.
He is a Portugal Under-20s international, and has been capped four times by the side.
Cardoso has also been called into Rui Jorge’s Under-21s squad, however he is yet to make an appearance for them.
Rangers were struck by an injury epidemic towards the end of the 2016/17 season, which resulted in Caixinha having to rely on the likes of David Bates, Aidan Wilson and Myles Beerman to fill his back four.
In order to challenge Celtic next season defensive reinforcements are needed, highlighted by the fact the Gers lost all but one of the six Old Firm derbies this campaign.
Caixinha’s side eventually finished third in the Scottish Premiership, 39 points behind their traditional rivals.