Complex sentence: Johnson had entered the league as an explosive power forward averaging 20 + points and 10 + rebounds, however, after the injury to his back, Johnson was forced to develop an all-around game with an improved outside shot.
Split into simpler sentences: Johnson had entered the league as an explosive power forward, averaging 20 + points and 10 + rebounds. However, after the injury to his back, Johnson was forced to develop an all-around game with an improved outside shot.