Atleti debating between renewing Adan and signing Joel

Atletico have got a dilemma: who would fit better as the number two goalkeeper to Oblak? The club do not know whether to continue with Adan or let him leave to try and re-sign Joel. That is what 'Mundo Deportivo' say and they investigate the reasons behind each movement.
If Adan stays, there are quite a lot of arguments in his favour. He is very aware of his role as number two, he always mixes with the squad and he will not have any problem. That said, the board have not been 100% satisfied with his performances when he has played.
If Joel comes, the Atletico bench will have an even better second choice keeper, but he may not accept playing second fiddle to Oblak. He is the number one at Real Betis so moving to Madrid would see him lose game time and it would be a step back in his career.
Lastly, it seems like it will be more expensive to sign Joel than renew Adan. The Betis shot stopper has a market value of 3.9 million euros and, if Adan's contract was extended, he is not expected to receive a massive pay rise because, after all, he would still be the number two.