Following their season sweep over the Raiders, the Broncos went home for a Sunday Night match-up with their AFC West rival, the San Diego Chargers.  With first place in the division on the line, both sides would play tough.  In the first quarter, the Chargers got the only score of the period as LaDainian Tomlinson scored on a 3-yard TD run on a 98-yard drive.  In the second quarter, the Broncos took the lead with RB Mike Bell getting two 3-yard TD runs.  In the third quarter, kicker Jason Elam completed a 42-yard field goal, while CB Darrent Williams returned an interception 31 yards for a touchdown. However, things started getting grim as Tomlinson (who historically had difficulty against the Broncos in Denver) exploded with a 3-yard TD run and a 51-yard touchdown reception.  In the fourth quarter, Elam would get a 38-yard field goal, but San Diego managed to wrap up the game with QB Philip Rivers completing a 5-yard TD pass to WR Vincent Jackson and Tomlinson getting a 1-yard TD run.  With the loss, the Broncos fell to 7-3 and second place in the AFC West. It would later be learned that safety Nick Ferguson had season-ending surgery to repair a torn medial meniscus in his left knee. He injured his knee after a 1st quarter interception.
Question: Who was unable to finish the season?
Answer: Nick Ferguson