Complex sentence: When it seemed Moreira was set to become Benfica's first-choice goalkeeper again, he suffered another injury, this time on his left knee, which forced him to again undergo surgery in July 2007, with this translating into four months off the pitch.
Split into simpler sentences: When it seemed Moreira was set to become Benfica's first-choice goalkeeper again, he suffered another injury, this time on his left knee. This forced him to again undergo surgery on July 2007, with this translating into at least four months off the pitch.