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.
Barcelona escape a scare on Philippe Coutinho's first start as Lionel Messi struck with a trademark free-kick to drag the La Liga leaders back from a goal down to beat Alaves 2-1 and restore their 11-point lead at the top.
Holders Barcelona reach the King's Cup semi-finals with a 2-0 win over Espanyol to overcome a first-leg deficit on a night when new signing Philippe Coutinho made his debut.
Argentine international defender Javier Mascherano is unveiled as the Chinese Super League's most high-profile signing in a year as he joins Hebei China Fortune from Barcelona.
Resurgent Barcelona are given a fresh boost when key defender Gerard Pique signed a contract extension until 2022.
Former Barcelona midfielder Ronaldinho, who won the World Cup, Champions League, Copa Libertadores and World Player of the Year award, is retiring from the game, his brother and agent Assis says.
Barcelona's Ousmane Dembele has been ruled out for "three to four weeks" in a new blow for the French forward, his club announce.
Luis Suarez steals the show with a brace and an assist as Barcelona fight back from two goals down to win 4-2 at Real Sociedad and restore their nine-point lead at the top of La Liga.
La Liga leaders Barcelona signed centre-back Yerry Mina from Palmeiras on a 5-1/2 year contract for a fee of 11.8 million euros ($14 million), the Spanish club say.
The cumulative sum of the buy-out clause of Barca's Lionel Messi, Luis Suarez, Osmane Dembele and Philippe Coutinho stands at a whopping 1700 million Euros.
Philippe Coutinho says he is targeting titles at Barcelona after finally completing his "dream" 160 million-euro ($192 million) move from Liverpool.
