The in-form midfielder, who has been one of Barcelona's most consistent performers in 2025, is dealing with what has been described as a minor problem in his right calf.
Club sources in Barcelona have said the issue is linked to the heavy challenge from Athletic Bilbao's Oihan Sancet during last weekend's league match. Sancet was shown a straight red card for the tackle, and although Lopez completed the game and even featured against Chelsea on Tuesday, he struggled to find his usual rhythm and was substituted in the second half.
Barcelona are already stretched in midfield, with Pedri still working his way back from injury. Hansi Flick admitted earlier this week that the team "missed Pedri's control and calmness" in the 3-0 defeat against Chelsea and added that the squad "cannot afford many more setbacks".
Lopez's absence is expected to last between 10 and 14 days, meaning he is likely to miss the upcoming league meeting with Alaves on Saturday and could also be out for the following fixture, depending on his recovery.
The 22-year-old has played a key role for Barcelona this season, contributing goals, assists and energy in a campaign repeatedly disrupted by injuries across the squad. Barcelona officials remain hopeful that Pedri will return this weekend, but losing Lopez so soon after another setback has underlined the fragile nature of their squad depth.
Flick has said the team "must stay positive and adapt" as they look to avoid further disruption during a packed run of fixtures. Barcelona are aiming to steady their form in La Liga, but with injuries continuing to pile up, the head coach faces another difficult balancing act.