A person with knowledge of the deal says the Cowboys have acquired quarterback Matt Cassel from Buffalo with Tony Romo sidelined at least seven games because of a broken left collarbone.
Other terms of the trade Tuesday weren't immediately available. The person spoke on condition of anonymity because the deal hadn't been announced.
Cassell has 71 starts in 90 games over 11 seasons, not counting the opener this year when he took the first snap for the Bills with Tyrod Taylor lined up at receiver.
Brandon Weeden is expected to start Sunday at home against Arizona, but Cassel is a veteran with far more experience than the fourth-year pro. Before the trade, owner Jerry Jones said on his radio show that Weeden was his starter. The Cowboys appear to be all-in despite being banged up on the offensive side of the ball. The NFC East is looking weak and Dallas' two wins at this point in the season look pretty big.