The Catalan giants had identified Williams as one of their primary targets earlier in the summer transfer window following his exceptional performances for Athletic and Euro 2024 winners Spain.
Prior to scoring twice for Spain at Euro 2024, including a goal in the final against England, Williams contributed with eight goals and 19 assists in 37 appearances for Athletic across all competitions last season.
There have been conflicting reports about the future of Williams, with one recently claiming that he is keen to join Barcelona, who have been told that they must activate his €55m (£47m) release clause if they wish to sign the attacker.
However, it is understood that the 22-year-old, who was recently handed the No.10 shirt at Athletic, is now planning to stay at his current club for at least another season, forcing Barcelona to search elsewhere for attacking reinforcements.
Barcelona step up pursuit of Leao
Barcelona have made two signings so far this summer, recruiting versatile attacker Dani Olmo from RB Leipzig for around £51m and young forward Pau Victor from Girona for £2.5m.
The cash-strapped La Liga club still have ongoing financial issues and are believed to be struggling to balance their books and register their new signings for the new season.
Nevertheless, Hansi Flick's side seemingly have funds saved for the purchase of a high-profile attacker and Mundo Deportivo reports that they 'will try' to sign AC Milan star Leao, who is valued between €90m (£77m) and €100m (£85m).
The report suggests that Barca have the funds to pursue a move for Leao, but it seems highly unlikely that they would meet Milan's asking price up front and would presumably want to negotiate a deal with several instalments due to their financial predicament.
Barcelona are said to be aware that negotiating a deal for Leao with Milan will be complicated, but they have an 'ally' in Jorge Mendes - the player's agent - who, along with Barca president Joan Laporta, will work 'against the clock' to attempt to get the deal done before the August 30 deadline.
Leao emerges as top target for Barcelona
It is understood that Barcelona have turned their attention to Leao after discovering that another of their targets, Luis Diaz, will not be leaving Liverpool this summer.
Both Bayern Munich's Kingsley Coman and Juventus' Federico Chiesa are viewed as affordable alternatives by Barcelona if they fail in their pursuit of Leao.
Since joining Milan from Lille in August 2019, Leao has established himself as a star player for the Italian giants, scoring 58 goals and providing 50 assists in 211 appearances across all competitions.
The 25-year-old, who primarily operates as a left-winger, was named Serie A Player of the Year in 2021-22 after recording 11 goals and 10 assists in 34 games to help Milan with the title that season.
Leao then contributed with 15 goals and 14 assists in 47 appearances last season and has subsequently caught the eye of several top European clubs including Barcelona, Paris Saint-Germain, Manchester United and Chelsea.
However, the Portugal international responded to transfer rumours in March and reiterated his commitment to the Rossoneri, where he is under contract until June 2028.