Brittney Griner is back in the U.S. -- and back dominating on a basketball court -- dunking in her first workout since her release from Russia ... though her WNBA future still remains uncertain.
Griner's agent, Lindsay Kagawa Colas, told ESPN that the 32-year-old Phoenix Mercury superstar grabbed a pair of Chuck Taylor sneakers and hit a court in San Antonio on Sunday for her first hoops sesh in nearly 10 months.
The workout was said to be "light" -- though it clearly went well .