If they finally decide to reinforce themselves, since the injuries of Luis Suárez and Ousmane Dembélé have let the front run off, The regulations only allow Barcelona to sign players who are free or militate in the First or Second Division of Spain. The regulations close the doors of the international market for new signings but also to recover loans. That is to say, Coutinho and Todibo may not return from Germany but Emerson (Real Betis), Rafinha (Celta) or Cucurella (Getafe) if they could leave their respective teams in Spain.The substitute could not play the Champions LeagueIf finally, as expected, Barcelona signs a striker, he can only serve in LaLiga. The regulations contemplated that Barça could register him for the Cup but was eliminated by Athletic in the quarterfinals. In the Champions League, the second deadline to register new players for the qualifiers has ended, so if you arrive, you will not be able to play against Naples or the subsequent rounds if the Blaugrana advance. Barcelona will have the option of signing although with certain limitations once the withdrawal of Ousmane Dembélé is confirmed until next season after the operation to be submitted to Finland on Tuesday.The culé team will have to manage the federation of Ousmane Dembélé, an exception that contemplates the regulation of the RFEF in its Article 119.1 b) of the RFEF regulations when there is an injury that has a footballer down for more than five months, to be able to undertake a new signing.