Complex sentence: After checking into the rehab center, Porter became a born-again Christian, married, and became a spokesman for the Fellowship of Christian Athletes; but his production on the field declined, never again approaching his 1979 levels.
Split into simpler sentences: After checking into the rehab center, Porter became a born-again Christian, married, and became a spokesman for the Fellowship of Christian Athletes. His production on the field declined after rehab, never again approaching his 1979 levels.