Barcelona have reportedly scouted PSV Eindhoven goalkeeper Jeroen Zoet with the view to signing the Netherlands international.
Cillessen's future at Camp Nou is far from certain, however, with the Dutchman strongly linked with a move away during the summer as he seeks first-team action.
According to Mundo Deportivo, should Cillessen move on in either January or next summer, Barcelona will launch a bid for Zoet having been impressed with his performances for PSV.
Zoet came through the youth system at PSV, and has made over 200 appearances for the Dutch club in all competitions.
The 27-year-old, whose current deal will run until the end of the 2020-21 campaign, is also an 11-time Netherlands international.