Midfielder Ronaldo Vieira also remains sidelined for the trip to Portman Road as he continues his comeback from a knee problem, but winger Stuart Dallas is back in the squad having missed United’s last nine games with an ankle injury.
Left-back De Bock joined Leeds on a four-and-a-half year deal from Club Brugge on Thursday but head coach Thomas Christiansen has revealed that the Belgian will have to wait to make his United debut.
Christiansen said: “He signed and he went back but now in a few days he will be back again with the team to train and to be ready for joining the group.
“He’s an interesting player at left-back - a position that we have been searching for so that will be a good signing.”
De Bock will be one of seven first-team players missing for the trip to Ipswich with No 10 Samu Saiz beginning a six-game ban for spitting at Robbie Willmott during last Sunday’s FA Cup third-round loss at Newport County and with right-back Luke Ayling out for the season with an ankle injury.
Vieira is also missing as he continues his recovery from a knee problem while striker Caleb Ekuban remains on the comeback trail after fracturing a bone in his foot.
Christiansen has also revealed that Everton loanee centre-back Matthew Pennington will miss the clash at Ipswich through sickness while Manchester United loanee left-back Cameron Borthwick-Jackson is sidelined with an ankle injury.
However, Northern Ireland international winger Dallas could finally be set to return from his lay-off with an ankle problem.
Providing an update as to those players whose participation was in doubt, Christiansen said: “Pennington is sick, he has been sick for a few days and he is not fit for this game.
“Ronnie is doing quite well and next week we expect him to be in with the team.
“Stuart Dallas is in the squad and we will see if he has possibilities to start in the XI.
“Caleb is still out and will need some time.”
On Borthwick-Jackson, Christiansen added: “He is not in the list because he got a kick or twisted his ankle - so he is out.”