Barcelona are watching Marseille midfielder Maxime Lopez.
Lopez, who's been performing at a very high level in recent weeks, is being followed by the Catalan club, according to Foot Mercato.
Maxime, a central midfielder, recently turned 19 and has rapidly become one of the French side's best players. The cited media say that his youth is one of the reasons Barça are most keen. So far this season, Lopez has provided five goals and scored one in 16 appearances.
If Lopez is ruled out, Barça are also following Borussia Monchengladbach's Mahmoud Dahoud as a Plan B.