BRASILIA (Reuters) - Brazilian President Dilma Rousseff will replace her agriculture and civil aviation ministers, in the first of a Cabinet shuffle that is not expected to change her economic team, a government source said.

The changes are expected to be announced later on Friday, the source, who asked not to be named, told Reuters.

Congressman Antônio Andrade from Minas Gerais state will become agriculture minister, replacing Mendes Ribeiro, who is recovering from brain tumor surgery. Both men belong to the PMDB, Brazil's largest political party and Rousseff's main ally in her unwieldy 17-party governing coalition.

Moreira Franco, currently secretary of strategic affairs, will move to civil aviation, replacing Wagner Bittencourt, the source said.

This switch follows criticism of last year's auction of private concessions to run three major airports, including the country's largest in Sao Paulo, which drew smaller and less experienced consortia than the government had hoped for.

Despite her government's failure to restore solid growth to Brazil's once-booming economy, which grew by a disappointing 0.9 percent last year, Rousseff is not expected to change her economic team headed by Finance Minister Guido Mantega.

Other Cabinet changes are in the works, and Rousseff is expected to name an ally to the newly created ministry of small and micro businesses.

Rousseff, whose popularity is in the high 70s, plans to run for re-election in 2014 and Cabinet appointments give her the chance to keep her coalition allies happy with government posts.

(Reporting by Jeferson Ribeiro; Writing by Anthony Boadle; Editing by Vicki Allen)