According to ESPN’s Adam Schefter, when the Detroit Lions and Los Angeles Rams began trade discussions to send Matthew Stafford to California, the first player that the Lions asked for in return was Aaron Donald. Strangely enough, trade talks continued from there on out.
When trade talks began between the Rams and Lions, the first player Detroit requested in a trade for QB Matthew Stafford was DT Aaron Donald, per sources. Rams told Lions, that's not happening, before the two sides later figured out the eventual compensation package.