But through it all, he has.
The experience has helped. The battles against first-teamers have been beneficial, which includes his third showdown with All-Star Damian Lillard in Portland on Tuesday night.
It has given Jackson a better understanding of scouting reports and schemes, how to operate against a game plan and how to adjust on the fly.
“People are starting to go under on pick and rolls and play different coverages, at times trapping,” Jackson said. “(I'm) just trying to get experience and pick it up better, figuring out what coverage they're in and then figuring out how to counter.”
When Westbrook is back, Jackson's most important minutes will likely come without Durant or Westbrook on the floor — in those crucial mid-game pockets where his attacking style will fit nicely into a second-unit that's been void of some playmaking in his absence.
And reinserted into that bench squad, Jackson returns a better player.
“I think he's improved in that area as far as managing the game,” Brooks said. “Understanding who's hot, who's not hot, who needs a bucket, who's open and just making sure he continues to make the right decisions. He's done a great job when Russell has been out.”
And that'll continue to pay off for the Thunder when Russell is back.