Christiansen revealed that an internal decision about Bellusci had already been made following a spat between the defender and some of the club’s supporters in a 5-1 win at Nethermoor.
Bellusci completed the first 45 minutes of United’s victory but was the target of sporadic booing and abuse prior to his substitution at the interval.
The Italian - a controversial figure during his three-year spell with Leeds - signed a number of autographs at half-time but was subjected to further chants against him as he walked to the tunnel in one corner of the ground.
He later tweeted: “Fortunately in this world we have the children to set an example to the adults!”
Christiansen is now set to make Bellusci’s position clear when he selects his squad for Leeds’ forthcoming tour of Austria.
The club’s head coach said: “I like to give them all the opportunity to show themselves. They have all had that. Now we will start taking decisions because players will arrive and some players have to leave.
“We have taken already our decision (on Bellusci) but I don’t want to come out now saying what we will do. You will see it through the week.”
Bellusci’s first two seasons at Elland Road were marred by suggestions that the centre-back was a disruptive influence in the dressing room and allegations that he and five other players feigned injury prior to a league game at Charlton Athletic in 2015, in an attempt to undermine then head coach Neil Redfearn.
Leeds sent him to Empoli on a season-long loan last July but plans for a permanent transfer there were wrecked by Empoli’s relegation from Serie A.
United gave an indication that Bellusci was surplus to requirements by granting him permission to miss the first week of pre-season training this summer, allowing him to remain in Italy and seek a transfer elsewhere.
Interest from Bologna, Cagliari and newly-promoted Benevento, however, has failed to lead to a firm offer and Christiansen has used him in both of United’s friendlies to date amid a shortage of experienced central defenders.
Bellusci, who also featured in Wednesday’s friendly win over Harrogate Town, has 12 months remaining on the four year deal he signed after joining from Catania in 2014.
Christiansen, who is close to the signing of Huesca number 10 Samuel Saiz, was satisfied with United’s performance at Nethermoor.
Stuart Dallas and Lee Erwin claimed two goals apiece either side of a tap-in from Marcus Antonsson.
“From my point of view we had a very good first half where we had rhythm in the game and played well between the lines,” Christiansen said.
“In the second half we didn’t play so fast as we should have. It was too slow in the passing but I’m also happy with the performance.”
United’s next friendly is away at North Ferriby United on Wednesday evening.