Complex sentence: In 2002 and 2005, the Buccaneers led the NFL in total defense (fewest yards allowed per game)--during Tomlin's tenure, the defense never ranked worse than sixth overall.
Split into simpler sentences: In 2002 and 2005, the Buccaneers led the NFL in total defense (fewest yards allowed per game). During Tomlin's tenure, the defense never ranked worse than sixth overall.