I just got the complete details of the five-year contract extension Carolina running back Jonathan Stewart signed Friday night.

The deal is worth $37.811 million and includes $23 million in guaranteed money. Stewart received a $9 million signing bonus and his salary-cap figure for 2012 jumped $1 million to $4.78 million. In 2013, Stewart will make $1 million in base salary and his cap figure will be $2.8 million.

In 2014, Stewart can pick up a $9 million option bonus, his base salary will be $1.5 million and his cap figure rises to $5.5 million. In 2015, Stewart’s base salary will be $4.25 million and his cap figure increases to $8.55 million.

In 2016, Stewart has a $5 million base salary and a $9.8 million cap figure. In the final year of the deal, the base salary is $5.5 million and the cap figure drops a bit to $8.5 million.

I think signing Stewart was a good move by the Panthers. It means he’ll stay in a backfield with DeAngelo Williams and Mike Tolbert. But the move comes with a downside.

Carolina already was looking at salary-cap trouble in future seasons. With Stewart’s deal, the Panthers now have $134 million committed toward the 2013 salary cap. The exact cap figure won’t be determined until next spring, but it’s safe to say the Panthers are at least $10 million over where the limit will be. They’re getting up there with the Philadelphia Eagles, who have a league-high $140 million committed toward next year’s cap.

It gets even worse as you look ahead to 2014, when the Panthers have $144 million committed toward the cap. Only the Eagles ($145 million) already have more cap space committed.

Heck, the Panthers already have $110 million committed toward the 2015 cap and that’s with only 18 players already under contract for that year.