Ajax Amsterdam boss Erik ten Hag believes the club's fortunes in the Champions League could have been different had the likes of Ghanaian midfielder Mohammed Kudus maintained fitness during the campaign.
The Dutch giants have been dumped out of the elite European inter-club championship after finishing third in Group D behind Liverpool and Italian outfit Atalanta.
A summer signing, Kudus was substituted after just six minutes on his Champions League debut when Ajax hosted Liverpool on matchday one of the competition in October.
"If everything had gone well, we could have qualified for the knockout phase. That was just not our expectations. We've lost core players for seven years in two years," ten Hag said, as reported by AD.
"The reality is that we don't have a Champions League side at the moment. We have to build on that again.
"Players like [David] Neres and Kudus, like [Ryan] Gravenberch, could have made a great move in their development had they been fit. Then it might have been possible [to qualify to the knockout stage]."
Ajax signed Kudus from Danish fold Nordsjaelland in a five-year deal in July. He was just beginning to find his feet in Amsterdam when he suffered the injury setback.
The 20-year-old has, however, resumed training after two months in the treatment room.
"A certain, broad core is needed, especially now that a lot of matches are coming up," ten Hag explained.
"All we can do is make sure we take action and have a wide selection so that we can accommodate it. It is not so important what our competitors are doing.
"What matters is what we do. Conditionally we are good. Hopefully, a number of players will reconnect soon. If we have to play with this group in January, it will be tough. If you look back this year, we have had immense problems.
"The injuries of [Hakim] Ziyech, [Daley] Blind, Kudus and Neres. All strongholds who can make a difference. But we were able to absorb it all in terms of football."
Kudus is expected to complete his injury return when Ajax face rivals PSV after the Christmas break in January.