Ching, who was out of action throughout April with a hamstring injury, was left out as Bradley opted for an inexperienced list of strikers.
LA Galaxy forward Edson Buddle, Real Salt Lake forward Robbie Findley and Herculez Gomez, who plays for Mexican club Puebla, all made the squad despite having just nine caps between them.
Hawaiian Ching, who plays for Houston Dynamo, featured as a second half substitute in Tuesday's 4-2 friendly defeat to the Czech Republic and has scored 11 goals in 45 internationals.
Bradley suggested Ching's omission was primarily a fitness and form issue given Buddle and Gomez have been in prolific scoring form.
"Plain and simple, Edson and Herculez have had real good stretches, scored a lot of goals. Brian has been such an important player but it's tough when you have an injury at an inopportune time," he said.
"It was extremely hard with the respect that we all have for Brian as a person, for the way he plays on the field and his commitment to the team."
The first choice striker will likely be Jozy Altidore with Clint Dempsey another option in attack.
The other six players to miss out, along with Ching, from Bradley's provisional 30-man roster were defenders Chad Marshall and Heath Pearce, midfielders Alejandro Bedoya, Sacha Kljestan and Robbie Rogers and forward Eddie Johnson.
Central defender Oguchi Onyewu, who made a tentative return against the Czechs after seven months out following a knee operation, was included.
"Like any player, we need to see that he continues to make progress. Last (Tuesday) night was a great start and we've got a couple more weeks, two more matches, so we'll get a good read as to exactly where he is as we get closer to the first game," said Bradley.
The United States will face England, Slovenia and Algeria in World Cup Group C. Before then, Bradley's team will face Turkey in Philadelphia Saturday and Australia in Roodepoort, South Africa, on June 5.
Goalkeepers: Brad Guzan (Aston Villa), Tim Howard (Everton), Marcus Hahnemann (Wolverhampton)
Defenders: Carlos Bocanegra (Rennes), Jonathan Bornstein (Chivas), Steve Cherundolo (Hannover), Jay DeMerit (Watford), Clarence Goodson (IK Start), Oguchi Onyewu (AC Milan), Jonathan Spector (West Ham United)
Midfielders: DaMarcus Beasley (Rangers), Michael Bradley (Borussia Monchengladbach), Ricardo Clark (Eintracht Frankfurt), Clint Dempsey (Fulham), Landon Donovan (Los Angeles Galaxy), Maurice Edu (Rangers), Benny Feilhaber (Aarhus), Stuart Holden (Bolton), Jose Torres (Pachuca)
Forwards: Jozy Altidore (Villarreal), Edson Buddle (Los Angeles Galaxy), Robbie Findley (Real Salt Lake), Herculez Gomez (Puebla).
