Rock will run in the 400-meter dash while Becker will compete in the hammer throw. Rock enters the trials with the 10th-best qualifying time at 45.12.
The 400-meter quarterfinals are scheduled for Sunday at 6:24 p.m. The semifinals are Monday at 9:25 p.m. and the finals are Thursday at 10:15 p.m.
The top three finishers, who have met Olympic performance standards, will earn a spot on the Team USA roster for the 2008 Olympic Games in Beijing, China.
Rock was a member of Team USA’s gold medal 1,600-meter relay at the 2004 Olympics in Athens.
Becker enters the Olympic trials as the 22nd qualifier in the hammer throw with a mark of 224 feet, 10 inches.
The hammer throw qualifying round is Monday at 9:25 p.m.with the finals set for Friday, July 4 at 9 p.m.

