Dallas Cowboys owner Jerry Jones has admitted that he replaced Rob Ryan as his side's defensive coordinator because his schemes were too complex.

The Cowboys face Ryan for the first time since he left the club last season when they play the Saints - who have shown marked improvement with the 50-year-old as their coordinator in the current campaign - on Sunday.

"I think so highly of Rob Ryan as a coach, frankly, as an imaginative coach and how he imaginatively approaches the game," Jones told 105.3 The Fan.

"He can have a lot going on, and we wanted less going on, but that doesn't make it right or wrong. He's basically implemented it and executed it the way he wants to do it down there and they're going to give us fits Sunday."

Dallas are 5-4 in their season going into their clash with the Saints in week 10.