Earlier this month, it was claimed that Manchester United were prepared to activate Roberto's £36m release clause in a bid to bring the versatile midfielder to Old Trafford.
Valverde, however, has insisted that he will 'absolutely count on Roberto this season'.
"Sergi Roberto is important for our team. We count on him absolutely for this season," Valverde told reporters.
Barcelona will travel to Real Madrid for the second leg of the Spanish Super Cup on Wednesday night looking to overturn a 3-1 first-leg deficit.