The Catalan club crashed out of the quarter-final of the Champions League last term, and lost the league to arch-rivals Real Madrid. Their only success in the previous campaign was winning the Copa del Rey.
Ernesto Valverde replaced Luis Enrique as Barcelona's new manager in the summer. The former Athletic Bilbao boss failed to win his first silverware at his new club as he saw his side suffer a 5-1 aggregate defeat to Real in the Spanish Super Cup.
Barcelona have already lost their star player Neymar to Paris Saint-Germain as the Brazil international completed a switch to Parc des Princes for a world-record fee of €222m (£200m, $262m).
The La Liga giants have already completed the signing of Paulinho as midfielder moved to Spain from Chinese Super League outfit Guangzhou Evergrande for €40m (£36.3m, $47.3m).
Suarez, who played for Barcelona between 1955 to 1961 has urged Valverde's men to fight together, irrespective of whether or not there will be new players added to the squad in the final two weeks of the summer transfer window.
"These two parties had little history and signings such as Dembele and Coutinho are not the solution," Suarez told Carrusel Deportivo.
"Barca [Barcelona] have to know that united and together they have to fight to get out of this, whether or not there are new players."
Barcelona have identified Coutinho and 20-year-old Dembele as the transfer targets. The Spanish side's general manager Pep Segura earlier admitted that the club are "close" to completing the double transfer. However, Liverpool manager Jurgen Klopp has reiterated his and the Reds' stand that the former Inter Milan man is not for sale.