As Brendan Rodgers’ squad jetted out to Dubai yesterday for a sunshine break, the 21-year-old centre back remained at home and will report to Rugby Park on Monday.
O’Connell, pictured, made seven appearances for Celtic at the start of the season, including the Champions League matches with Astana, Hapoel Beer-Sheva and Barcelona.
However, he was pushed down the pecking order following the return to fitness of Jozo Simunovic and the arrival of Kolo Toure.
Rodgers indicated in November that it would be best for the Irishman, who has also had spells with Oldham Athletic and Cork City, to gain further experience on loan and now a deal has been struck with Killie.
The Celtic manager said: “He did very well in pre-season but the team has changed and he is not getting so much game time. So if he can get out on loan that will give him the game time he needs to develop.” Killie were so short at the back in their final game of 2016 against Partick Thistle that Gary Dicker had to move into central defence to play beside youngster Iain
Regular centre backs Miles Addison and Scott Boyd are injured, while Jonathan Burn is heading back to parent club Middlesbrough and Will Boyle has returned to Huddersfield Town along with
striker Flo Bojaj.
Manager Lee Clark is also hoping to bring in three players from Newcastle United’s development squad – keeper Freddie Woodman, forward Callum Roberts and midfielder Sean Longstaff.