No end to difficulties for troubled RadioShack rider.

Andy Schleck has prematurely left the Tirreno-Adriatico during the sixth stage from Porto to Sant'Elpidio.

The RadioShack rider walked out in the first half of the stage after a vicious early velocity. Schleck has suffered a troublesome year, clawing his way back from a severe injury incurred last year.

He managed to complete the GP di Camaiore last month, the first time he had finished a race since finishing the Liege-Bastogne-Liege last year.