It's been a tough season for Adrián Marín. He made his Primera debut, got very good press, but then came up with an injury that's kept him off the pitch since November. Apparently his problem is a kind of iliotibial band syndrome; this has several causes, but biomechanical and training factors are usually what causes it to happen--it's a fairly common injury among runners.
According to this, most cases respond to rest, icing, etc. but when it doesn't, and in this case it hasn't, surgery is indicated. Marín should be ready to go by the end of the summer; it's a minimally invasive surgery than involves lengthening a tendon to relieve the problem.
We wish Adrián well and look forward to his return next season!