Dallas Cowboys owner Jerry Jones has said that Jason Garrett is still "evolving" his coaching style.
The 47-year-old took over as the head coach of the NFC East side during the 2010 season, and is yet to take the club to the playoffs.
Jones told the Star-Telegram: "He's a young coach, and one of the things you've got to remember, that you should remember, is that, as a young coach, your system should be evolving.
"There shouldn't be a system that you've hung on for years and years and years. [Former Cowboys offensive coordinator] Ernie Zampese, for instance. Jason's fresh in his evolving, as far as scheme is concerned.
"Plus we've added a [quarterback Tony] Romo emphasis in it. That's changed, too. We've had some dramatic change with the Cowboys since last year."
The Cowboys play the San Diego Chargers tomorrow.