Barca join running to sign in-demand midfielder.
The Catalan giants may be about to lose the young Brazilian for the rest of the season, and manager Luis Enrique will need more depth in that central area.
Gundogan has been linked with Barca before, but the German international seemed to come closest to moving to the Premier League in the summer with either Arsenal or Manchester United.
Champions League team of the week: Cristiano Ronaldo & Paul Pogba joined by Chelsea & Man City stars
Arsenal, Liverpool & Chelsea £35m transfer target in extraordinary 706-minute goal drought
Manchester United news
However, according to Sport, it seems likely that the 24-year-old will be one of Barcelona’s main targets for the middle of the season, as they could be busy at the end of their transfer ban.