NBC emailed me their gymnastics TV Schedule below:

THIS WEEK'S OLYMPIC TRIALS TELEVISION SCHEDULE
 
Sat., June 21               Gymnastics                          NBC                4:30-6 p.m. ET
Sat, June 21                Gymnastics                          NBC                8-10 p.m. ET
Sun., June 22             Gymnastics                           NBC                7-9 p.m. ET