Concern grew after Baleba was forced off a session in Vienna, and he sat out the following day's friendly against Strasbourg as a precaution, with scans on his ankle and foot showing he will be sidelined for "a few weeks" – though Albion understand the results are better than initially feared.
The 22-year-old, who is under contract until 2028 and valued at close to £60m, cut a relaxed figure on the touchline throughout, sharing jokes with team-mates as Brighton eventually won the 120-minute contest 4-3.
Yasn Ayari and Pascal Gross took up the midfield berths for the opening 45 minutes, before Harry Howell and Malick Yalcouye were introduced; of the pair, Yalcouye – who spent last season on loan at Sturm Graz and Swansea – is regarded as closer to Baleba in playing style, if not physique.
Jack Hinshelwood remains a further option, though manager Fabian Hurzeler has preferred to use him further forward in recent months. Transfer speculation around the Cameroon international has been notably quieter than a year ago, when he was strongly linked with Manchester United.
Elsewhere, West Ham United have confirmed the signing of Joel Veltman, who spent five years at Brighton before his contract expired this summer, on a free transfer. Signed by Brighton from Ajax for £900,000 back in 2020, the Dutchman went on to help the Seagulls finish sixth in the Premier League in 2022-23 and reach their first-ever European campaign via the Europa League; across his career he has made more than 450 appearances for the two clubs combined, including over 165 in the Premier League.
"We know that West Ham need to be in the Premier League, and for sure that is our goal for the season," Veltman told the club's website. "I think I bring my experience, my winning mentality and togetherness.
"I bring leadership – I've been the captain at Ajax, and I enjoy talking to my team-mates and using my experience to help the squad."
West Ham's director of player recruitment, Nils Koppen, added: "He knows English football very well, is highly motivated and is ready to give his all as we begin our quest to win promotion back to the Premier League."
Veltman, who has 28 caps for the Netherlands and helped them reach the World Cup semi-finals in 2014, also featured at Euro 2020.