The last time the Dallas Mavericks did not have J.J. Barea available for an extended period of time was the 2016-17 season when he missed more than half of the games due to injuries. Before that, the Mavs were missing him from 2012-2014 when they let him go to the Minnesota Timberwolves.
Aside from those years, Barea has been a key player off the Mavericks bench essentially every season since the team won the NBA Championship. Over the past few years, he has been acting as the floor general for the second unit and a locker room leader at all times.