Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
Look for "SAAver" Coach awards on aa.com for PTY-DFW-PDX. If you find any, they should be bookable for 20K BA Avios. But, if the DFW-PDX flight is on AS metal, that segment will need to be booked as a separate redemption (by calling the BAEC Service Center) to avoid being charged BAEC's higher, multi-partner redemption rate.