He is known for publishing an early acceptance of the Copernican theory, he was also the most important Augustinian scholastic thinker from the second half of the XVI century.
[2] This publication made him one of a very small number of Catholic scholars of the sixteenth century who set out an explicit accommodation with the ideas of Copernicus.
In Philosophia prima pars, written at the end of his life, he rejected Copernicanism as incompatible with Aristotelian theory on natural philosophy.
[5] The work of Zúñiga was placed on the Church's Index, together with Copernicus' De revolutionibus, by a decree of the Sacred Congregation from March 5, 1616: (...) This Holy Congregation has also learned about the spreading and acceptance by many of the false Pythagorean doctrine, altogether contrary to the Holy Scripture, that the earth moves and the sun is motionless, which is also taught by Nicholaus Copernicus's 'On the Revolutions of the Heavenly Spheres' and by Diego de Zúñiga's 'On Job'.
(...) Therefore, in order that this opinion may not creep any further to the prejudice of Catholic truth, the Congregation has decided that the books by Nicolaus Copernicus ('On the Revolutions of the Heavenly Spheres') and Diego de Zúñiga ('On Job') be suspended until corrected.