Brent isn't eligible to play in a NFL game until Nov. 23 at the New York Giants. However, he's been practicing for at least a week.
Brent was cleared to make the trip by NFL and law enforcement officials. He's on probation after his conviction of an intoxication manslaughter charge that resulted in the death of his best friend and former Cowboys practice squad player Jerry Brown.
Team officials have praised Brent's work in practice and have said he just needs to get his weight down. Whether he plays in a game this season is uncertain, but the Cowboys think enough of Brent where they signed him to a one-year non-guaranteed contract for 2015.
The entire 53-man roster including practice squad players are headed to London where the Cowboys will play the Jacksonville Jaguars.