User blog comment:Legionwrex/How did Saren reach the Citadel?/@comment-3228423-20130507041453/@comment-3228423-20130507044218

Who knows what those implants did to Saren. As far as we know it implanted mass effect generators inside him so that SOB could fly.

Maybe that, though I still say it was Linron. She definitely has the motive to do so anyway.