Uefa allows only three new signings to be registered for the last-32 stage and with four players coming in at Celtic Park in January, one had to be omitted.
Bayo is yet to play a game for the Scottish champions since his arrival from Slovakia's Dunajska Streda while Jeremy Toljan, Oliver Burke and Timothy Weah have all seen first team action.
The 21-year-old who last played a match in mid December is presently working his way back to top form in an attempt to make Brendan Rodgers' matchday squad.
Earlier this season, Bayo scored three goal goals in four games for Dunajska Streda in the Europa League qualification round before they were bundled out by Dinamo Minsk with a 7-2 aggregate win.
The Bhoys welcome Valencia to Celtic Park for the first leg of the encounter on February 14.