The Chilean faces up to 15 days on the sidelines after picking up a slight tear in his right adductor during the latter stages of his side's 3-1 win against Sporting Gijon
The former Udinese star had only came on with half an hour to spare as a replacement for Cesc Fabregas on the night but, despite the Blaugrana eventually coasting to a 3-1 victory, the triumph has been softened with the news that the summer signing ended the match in discomfort.
The club's medical team have since reported that Alexis sustained a "slight tear in the adductor of his right leg", although it is understood that it is not a recurrence of the setback which previously kept him on the treatment table for the first two months of the season.
Alexis, who represented Chile against Ghana in midweek, has scored 11 goals since his €37million transfer from Udinese last summer.
His team-mates Andres Iniesta, Seydou Keita and Xavi were on the scoresheet as Barca saw off Sporting.