Davies, who was severely injured in a horrific single-car accident in October that claimed the life of another passenger, had tried for seven months to recover fully from his injuries but failed to do so in time.
That left U.S. Coach Bob Bradley with the task of finding at least two forwards who can complement probable starter Jozy Altidore on the U.S. front line.
On Tuesday, the deadline set by FIFA for naming preliminary rosters, Bradley turned to the Galaxy's Buddle, the top goal scorer in Major League Soccer this season, and to Gomez, the co-leading scorer in the Mexican league with Puebla last season.
Bradley's roster lists Clint Dempsey as a forward, although the Fulham star can also play wide on either wing. Dempsey is an almost certain starter, but which position he plays could be determined by which of the other forwards Bradley ultimately selects.
The 30 players will report to a pre-World Cup camp at Princeton University starting this weekend and will be available for warmup games against the Czech Republic in Hartford, Conn., on May 25 and Turkey in Philadelphia on May 29.
After that, Bradley will cut the roster to the 23 players he will take to South Africa, where the U.S. plays England, Slovenia and Algeria in the first round of the June 11-July 11 world championship.
The roster of 30 includes all but two of the players who were on the field when the U.S. upset European champion Spain in the semifinals of the Confederations Cup in South Africa last year and then narrowly lost to Brazil in the final.
Not selected were forwards Conor Casey of the Colorado Rapids and Davies.
The likelihood was that Bradley already had decided not to bring Davies into camp, but the final decision was made easier when Davies' French club, FC Sochaux, said Tuesday that it would not release him.
"Charlie has shown incredible heart and determination to reach this point in his recovery," Bradley said.
Buddle, whose only appearance for the U.S. national team came in 2003, was overwhelmed by the news, although he had been expecting it after scoring nine goals in the first eight games of the MLS season.
"It has always been my dream to represent my country and play in the World Cup," Buddle said.
There is no guarantee that he will do so because Gomez, who has been scoring frequently for Puebla, and Johnson, who is doing the same for Aris, will provide stiff competition. Ching and Findley are lesser goal-scoring threats, but do offer Bradley experience and speed, respectively.
Johnson's Aris teammate Freddy Adu was not invited to camp, and other notable omissions included Colorado defender Marvell Wynne and Real Salt Lake midfielder Kyle Beckerman.