Complex sentence: The fourth season saw the introduction of Dick Grayson (voiced by Evan Sabara) into the show; this was due to the "Teen Titans" animated series had been cancelled early in the year before this season started.
Split into simpler sentences: The fourth season saw the introduction of Dick Grayson (voiced by Evan Sabara) into the show. This was due to the "Teen Titans" animated series being cancelled earlier in the year, before this season started.