Dallas Cowboys owner and general manager Jerry Jones has ruled out the possibility of making wholesale changes to the team's roster.

The Cowboys have not reached the playoffs for four years despite boasting a number of experienced players such as Tony Romo, Jason Witten, DeMarcus Ware, Miles Austin and Jason Hatcher.

Jones embarked upon a drastic reshuffle when he first took over the team 25 years ago today, but he has revealed that he could not do the same now even if he wanted to due to the salary cap.

"You can't do what I did in 1989 because of the contracts and cap," Jones told reporters at the NFL scouting combine.

"The system automatically creates about a third turnover, but it also creates contractually for clubs a situation where you cannot just strip it.

"You couldn't even field a team with the hits against your cap by cancelling the contracts."

Jones's initial overhaul worked wonders in the end, turning an ailing Cowboys team into three-time Super Bowl winners in the space of four years in the early 1990s.