Jansen (forearm) will begin a minor-league rehab assignment with Double-A Frisco on Tuesday, Jeff Wilson of AllDLLS.com reports.
Jansen has been sidelined since early June while recovering from a right forearm injury, but he's all set to return to game action this week. The catcher was eligible to be activated from the 60-day injured list Wednesday, so whenever the team feels like he has shaken off the rust and gotten back up to speed, he'll be able to return to the major-league roster. Considering how long he's been out, it wouldn't be a surprise if he requires a lengthy rehab assignment, but a return to the Rangers before the end of August appears likely.