Complex sentence: He retired in 2002 after injury problems, and took up golf and actually turned professional, however the knee injury that ended his career could not take the strain of being a pro, and he retired and now plays recreationally.
Split into simpler sentences: He retired in 2002 after injury problems, took up golf and actually turned professional. However, the knee injury that ended his career could not take the strain of being a pro, and he retired and now plays recreationally.