Complex sentence: On November 5,2010, MSNBC announced that Hayes would be filling in for Keith Olbermann during Olbermann's suspension; however, the network later backtracked after finding out that Hayes had also made political contributions--the issue over which Olbermann was being suspended.
Split into simpler sentences: On November 5,2010, MSNBC announced that Hayes would be filling in for Keith Olbermann during Olbermann's suspension. However, the network later backtracked after finding out that Hayes had also made political contributions--the issue over which Olbermann was being suspended.