Arnaiz has been one of the few players to force their way into first team reckoning form the academy in recent years. The former Real Valladolid man is enjoying a fine season with Barca's B team and has shone on his brief outing with the first XI, scoring three goals in four appearances in the Copa del Rey.
However, the forward has suffered a major blow in the form of a groin injury, with Barca reluctant to put a date on his return. The 22-year-old will certainly miss Barca B's upcoming games against Tenerife and Granada, with the club then planning on taking things week-by-week as they look to avoid rushing him back into action.
The injury comes as a blow for Barca B boss Gerard Lopez and first team manager Ernesto Valverde, with neither coach able to call on the player in the weeks to come.