Barcelona have confirmed that midfielder Arthur Melo will be ruled out for up to four weeks after suffering a hamstring injury.
The Brazil international has enjoyed an encouraging first season at Camp Nou following his arrival from Gremio, making 27 appearances and becoming a mainstay of the Blaugrana midfield.
Having been handed the No.8 shirt, the 22-year-old has been compared to Andres Iniesta, and alongside Ivan Rakitic and Sergio Busquets the trio have helped Ernesto Valverde's side build a six-point lead at the top of La Liga.
Arthur now, though, will be forced to watch on from the sidelines as Barca enter a critical stage of the season.
"Tests have confirmed that first-team player Arthur Melo has a muscular injury to the left femoral biceps," a club statement read.
"The approximate down time is between three and four weeks."
That means Arthur will certainly miss Sunday's trip to Athletic Club as well as upcoming Liga fixtures against Real Valladolid and Sevilla.
He will also be forced to sit out the first leg of Barca's Champions League last 16 tie against Lyon in France, though he should be fit to return by the time the second leg is played in Catalunya on March 13.
Perhaps most pertinently, though, he will almost definitely miss the second leg of Barca's Copa del Rey semi-final against Clasico rivals Real Madrid on February 27, with the tie neatly poised following a 1-1 draw at Camp Nou on Wednesday.
He also faces a race against time to be fit for Barca's Liga clash at Santiago Bernabeu four days later, with that game scheduled for three weeks' time.
A likelier return date is set to be over the weekend of March 10 when the defending Spanish champions host Rayo Vallecano.
Arthur's absence means there could be an opportunity for Philippe Coutinho to step into the team should Valverde believe he can provide from a deeper midfield role.
The former Liverpool man has struggled to establish himself in the starting 11 this term, and with Chelsea and Manchester United reportedly keen, he could be set to leave Camp Nou this summer.
Other potential replacements for Arthur could be Arturo Vidal or Sergi Roberto while January signing Kevin-Prince Boateng does have experience of playing in midfield, though he was largely brought in to provide cover up front for Luis Suarez.