Barca remain on 34 points and lead second-placed Real Madrid by four but their rivals now have two games in hand, while the victory moved Las Palmas up to 14th place on 15 points.
Barcelona cited UEFA rules preventing clubs from changing stadiums during the Champions League's opening phase and "the logistical difficulties and extra costs" if they kept open two grounds at the same time.
A product of Barcelona's youth academy, Bernal has made three league appearances since his debut for the senior team in their LaLiga opener against Valencia.
Barcelona's next away game is at Serbian club Crvena Zvezda in Belgrade on November 6.
Olmo will miss Barcelona's opening Champions League matches against Monaco and Young Boys.
The German coach took charge of his first home match since he was appointed in May.
Barcelona signed Spain star Dani Olmo from RB Leipzig on Friday for a reported 60 million euros ($65 million).
New Barcelona coach Hansi Flick on Thursday hailed the performance of the Spanish club's teenage winger Lamine Yamal at Euro 2024, calling it "unbelievable".
The No. 19 at Barcelona previously belonged to Vitor Roque for a brief period.
Pedri's goal helped Barcelona earn an agonising 1-0 win over Celta Vigo to move back top of La Liga on Sunday.
Inter Milan are teetering on the brink of full-blown crisis as they prepare for the visit of Barcelona to the San Siro, which will likely have a huge bearing on their chances of making the knockout stages of the Champions League.
Relentless striker Robert Lewandowski pounced twice as Barcelona hammered 10-man Elche 3-0 to move a point clear at the top of La Liga on Saturday.
Barcelona striker Pierre-Emerick Aubameyang said Wednesday his jaw was injured during a violent armed robbery at his home but he expects to recover "in no time".
Barcelona were held 0-0 by Rayo Vallecano in their opening game of the La Liga season and had captain Sergio Busquets sent off late on.
Barcelona's attempts to establish themselves once again as a force in La Liga and the Champions League this season have seen the heavily-indebted Catalans gamble with their future to enable a striking summer spending spree.
La Liga is reportedly refusing to allow FC Barcelona to register new players ahead of the new season.
Uruguay great Luis Suarez made his second debut for his boyhood club Nacional on Tuesday but could not prevent them from falling to a 1-0 defeat at home to Atletico Goianiense.
Spanish football club Barcelona sold a 25% stake in its audiovisual studio to digital fan token firm Socios.com for 100 million euros ($102 million), club chief Joan Laporta said on Monday, as the LaLiga giant steps up efforts to bring in revenue to register new players.
French winger Dembele opened the scoring with his third goal in two matches. From a pass by Raphinha he unleashed a right-footed blast into the bottom right corner of Carlos Coronel's net.
