Barcelona have been given the green light to sign another striker, following an untimely injury to Ousmane Dembele, but have just a 15-day window in which to get a deal done.The Blaugrana had been pushing the relevant authorities for permission to bolster their ranks.Luis Suarez has also been stuck on the sidelines of late, leaving the Liga champions short of options in an important area of the field.They do still have six-time Ballon d’Or winner Lionel Messi and France international Antoine Griezmann at their disposal.Rules in Spain do, however, stipulate that reinforcements can be brought in outside of the designated transfer windows in the case of an emergency, and Barca have seen it confirmed that they tick the relevant boxes.Dembele has been ruled out for the remainder of the season after undergoing surgery on a hamstring problem.Those at Camp Nou have made it clear for some time that their plan was to get another body on board – with teenage talent Ansu Fati the only alternative to Messi and Griezmann after Carles Perez and Abel Ruiz saw departures sanctioned during the winter window.Barca have been freed to step up their bid for further firepower but will need to move quickly and not cast their net too far from home.The Royal Spanish Football Federation (RFEF) dictates that players can only be acquired at this time if they are free agents or tied to another La Liga club.As such, those in Catalunya will not be allowed to shop outside of a domestic market if money is to be spent.Any selling club will also be prevented from bringing in reinforcements themselves, which could further hinder Barca’s efforts.If a deal is to be done for another frontman, then said addition would only be eligible for La Liga competition and not become available to Quique Setien in the Champions League.Several options have been mooted for Barca, although many have also been ruled out.Among those considered to still be realistic targets are Angel Rodriguez of Getafe, Lucas Perez of Alaves, Levante forward Roger Marti and Leganes goal-getter Martin Braithwaite.