Croatian international will need to cut his salary to join Luis Enrique's side.
Catalans host Basque side following a 2-1 defeat at San Mames.
Sergio Ramos also made his comeback on Monday.
Spanish midfielder is believed to be closing in on a loan move to Ibrox.
18-year-old playmaker will continue his development in the fourth-placed team of the Eredivisie.
Second keeper missed the first-leg due to injury.
Captain yet to play a game since December's Club World Cup final.
Croatia international was left out of the squad in Catalans' draw at Villarreal.
Real Madrid are also reported to be monitoring the 20-year-old England international.
Barcelona looking to bounce back from midweek defeat against Athletic Bilbao.
Portugal international is back in Zidane's 19-man squad after being rested against Sevilla.
Catalans conceded two early goals, but Messi gave them some hope ahead of the second leg.
Real Madrid looking to extend lead over Barcelona in La Liga title race.
Los Blancos took a huge step towards the last eight of the Copa del Rey with a 3-0 victory.
Rodriguez, 25, scored twice in Real's 3-0 win over Sevilla in the Copa del Rey.
Luis Enrique is out of contract at the Nou Camp at the end of the season.
Catalans are reportedly in negotiations to sign Shakhtar Donetsk right-back Darijo Srna.
Jeremy Mathieu has received medical clearance but is out of the 18-man squad.
Catalans visit the Basque side before a La Liga trip to Villarreal.
Real are chasing records, while the Catalans have some catching up to do.
However, Los Che's plans could now be subject to change following the resignation of Cesare Prandelli.
Recent reports claim that Jose Mourinho is likely to meet his £84.6m release clause in the summer.