#2 Rafinha

Being injury prone and having failed to make use of all his opportunities, Rafinha could be looking down the barrel at Barcelona. The likes of Frenkie de Jong, Sergio Busquets, Ivan Rakitic, and Arturo Vidal are ahead of him in the pecking order in the midfield and this could well eliminate Rafinha's playing time at the club next season.
Barcelona could still require funds to make a few signings this summer and hence, a few players could be sold this summer. With his presence at the club helping neither him nor Barcelona, it would be best if Rafinha leaves the Catalans in this transfer window.
#1 Samuel Umtiti

At the end of the 2017/18 season, France's Samuel Umtiti was considered as a long-term solution for Barcelona's defence and an ideal partner to Gerard Pique in the current setup. After his successes at the World Cup last year, Umtiti was expected to continue his performances for his club.
However, injuries and lack of form reduced Umtiti's game time last season in which he put on the Barcelona shirt just 14 times. A reliable performer who could be available for selection every week is a priority for Ernesto Valverde and it seems that Umtiti does not fit this bill.
Umtiti still has decent value in the market and it could just be the right time for Barcelona to make use of it.