To make room for Elliott, the team released veteran running back Alfred Morris.
The Cowboys had been granted a roster exemption after Elliott signed his six-year, $90 million extension on Wednesday that included $50 million in guarantees, according to sources.
Elliott took part in all three practices during the week and was pronounced fit to go, but coach Jason Garrett would not comment on what kind of role the running back would play after missing all of training camp.
The Cowboys signed Morris on July 30 with Elliott skipping camp. He played for the Cowboys in 2016 and 2017 and spent last season with the San Francisco 49ers.
Had Morris been on the active roster Saturday, his $930,000 base salary would have been guaranteed for the season.
It is possible the Cowboys could look to re-sign Morris. Rookie Tony Pollard, Jordan Chunn -- who spent last season on the practice squad -- and Jamize Olawale are the other running backs on the 53-man roster with Elliott.