Complex sentence: Carreras then lived his most steady period at RCD Mallorca, although never an undisputed starter; he achieved promotion in his first season, then proceeded to amass roughly over 100 overall appearances.
Split into simpler sentences: Carreras then lived his most steady period at RCD Mallorca, although never an undisputed starter. He achieved promotion in his first season, then proceeded to amass roughly over 100 overall appearances.