The Bosnian midfielder missed Saturday’s 3-1 win over Segunda B side Gimnastic Tarragona after testing positive for Covid-19 at the end of August and has been left out of the squad for this match as well.
Pjanic, who signed from Juventus in a €60 million deal in June, has been back in training after a period of quarantine and arrived in Barcelona on Thursday night.
Koeman opted for a 4-2-3-1 formation in the match against Gimnastic and looks to have repeated that system tonight.
The Dutch coach gave all of his players 45 minutes in the first friendly of pre-season, but could hand some extra playing time to some of his squad in the meeting with Girona at the Johan Cruyff Stadium.
Captain Lionel Messi starts again after he played the first half against Nastic, but Luis Suarez and Arturo Vidal have been left out of the squad for the second game in a row and could leave the Catalan club in the coming days.
Goalkeeper Marc-Andre ter Stegen remains sidelined after undergoing surgery on a knee problem last month.
Defender Samuel Umtiti is also still injured, while fellow centre-back Jean-Clair Todibo has not been included in the squad despite receiving the all-clear following a positive coronavirus test last month.
Barcelona start LaLiga, which kicked off at the weekend, in the third round of the competition after featuring in the Champions League quarter-finals last month.
Barcelona XI: Neto, Roberto, Pique, Araujo, Alba, Busquets, De Jong, Trincao, Messi, Coutinho, Griezmann