Bilbao's build-up to the new campaign has been dominated by speculation over the futures of striker Fernando Llorente and midfielder Javi Martinez.
Llorente has told the club he will not extend his current deal when it runs out at the end of the season, attracting interest from across Europe, while Martinez has been linked with a move to Bayern Munich.
It has prevented Athletic from being able to prepare for tomorrow's opener away from the spotlight, but midfielder Carlos Gurpegui is confident the team can get on with their job.
"I'm really looking forward to the new season," he said on www.athletic-club.net.
"Exciting times are ahead. We have a young team, we have always been competitive and will continue to be. I can't wait to run out on the pitch.
"The atmosphere is positive. There have been distractions but we will try and give everything we can to ensure Athletic finish as high up the table as possible to make our fans proud."
Bilbao have doubts over the fitness of Iker Muniain, who has a right leg injury. Fernando Amorebieta is recovering from groin surgery while Jon Aurtenetxe is also sidelined with a groin injury.
Betis have had distractions of their own during pre-season, with club president Miguel Guillen among those involved in a dispute with the Football League (LFP) over television rights and money.
Several La Liga clubs have voiced their unhappiness at what they perceive to be a bias towards Barcelona and Real Madrid, threatening to strike over the issue.
Action was avoided following a meeting this week between the clubs and the LFP, but Guillen is aware it will take time for the matter to be fully resolved.
"We must have a solution but it will not be ready tomorrow," he told Betis' radio station.
"It is nevertheless an important step that a large group of clubs strongly disagree with some of the decisions made by the LFP.
"It is a very important step that the president of the Sports Council is aware of which issues need dealing with and will now intervene and help solve these structural problems which are taking their toll on the league."
On the pitch, Joel Campbell is expected to return to training today after playing for Costa Rica in midweek.