After going down in the third quarter of Monday night's 21-7 win over Carolina, Jones was said to have suffered a knee strain, which kept him out of the last quarter. However, after mobility in the knee failed to improve today, Jones underwent an MRI, which revealed a sprain.
Owner Jerry Jones expressed concern over the injury this morning.
Jones will join Marion Barber--who missed Monday night with a quadriceps injury--as the second Cowboys' runner to suffer leg injuies in as many weeks, leaving Tashard Choice as the only currently healthy Dallas running back.
The good news for Dallas is that Barber seems to be on his way to a quick return. Wade Phillips described him as "close" with respect to Monday's game, but was held out as a precautionary measure, and it seems unlikely that Barber will miss another week.