When Chelsea signed Marko Marin back in 2012, we all knew his injury history and knew that if there was one thing that would prevent him to playing up to his theoretical potential, it would be the injuries. So when injuries prevented the German Messi — there was a certain level on non-irony in this nickname once — from ever really making an impact at Chelsea, hopefully none of us were surprised. It sounds like he wasn't either.
"That's easy to explain. At Chelsea I had a strong pre-season, but then I was injured shortly before the season and was out for four months."
"During the season I came to a total of 16 games. But I wanted more, I did not want to wait for my chance. Then Sevilla came up to me and I went on loan."
-Marko Marin; source: BILD via Sport Witness
And the rest, as they say, is history. Marin actually seemed to have success at Sevilla but they opted against making him a permanent signing. Marin struggled with injuries once again the next season at Fiorentina and Anderlecht, but did find a certain measure of success at Trabzonspor last year. He's now with Olympiakos Piraeus, having sealed a permanent move over the summer. He's still just 27 (younger than Willian!) and he collected an assist in his first Greek Super League match. Best of luck to him!