Thompson has undergone examinations over the last two days and had neurological tests on Friday morning, resulting in the diagnosis.
The injury occurred when Thompson was kneed in the head by the Houston Rockets' Trevor Ariza during Game 5 of the Western Conference finals. After the game, the Warriors announced that the guard began experiencing “concussion-like symptoms” following the win.
On Thursday, Thompson's agent told USA Today that his client did not have a concussion and that testing showed "no issues."
Thompson must pass the NBA's concussion protocol in order to be cleared to play again. Golden State said he will be "evaluated daily" and did not have a timetable for his return.
The play where Thompson sustained the concussion can be seen below.
Game 1 of the NBA Finals will be held on June 4. The Warriors beat the Rockets in five games to advance to the Finals, where they will meet the Cleveland Cavaliers.
Thompson is averaging 19.7 points and 3.7 rebounds in 15 postseason games.
- Molly Geary