Liverpool progressed to the last 16 of the Champions League as runners-up in Group A, setting up a two-legged tie with Group F winners Real Madrid.
Those clashes will take place at Anfield on February 21 and then the Bernabeu on March 15, with a place in the quarter-finals up for grabs.
After naming a 24-man squad for the group stage, Liverpool will then be required to submit a revised list to UEFA by 11pm GMT on February 2 for the knockouts.
UEFA rules stipulate a maximum of 17 non-homegrown players, with a minimum of eight locally trained players of which at least four must be club-trained.
Klopp’s initial squad was comprised of three club-trained players, four association-trained players and 17 others.
With the January signing of Cody Gakpo, another non-homegrown player is added to the squad, while Naby Keita was also not registered in September along with association-trained Alex Oxlade-Chamberlain.
Changes are then required if Klopp wishes to register all three of those – which is almost certainly the case.
A tough decision over which non-homegrown players will be removed from the squad for the knockout stages is at least made easier as Bajcetic now qualifies for List B.
Clubs in the Champions League are permitted to register an unlimited number of players to List B no later than 11pm GMT on the day before any match.
However, to be eligible, UEFA explains that they must have been “born on, or after, January 1, 2000 and have been eligible to play for the club concerned for any uninterrupted period of two years since their 15th birthday.”
Liverpool’s Champions League group stage squad
Defenders: Van Dijk, Gomez*, Konate, Matip, Phillips**, Alexander-Arnold*, Robertson, Tsimikas, Ramsay
Forwards: Salah, Firmino, Jota, Diaz, Nunez, Carvalho**
List B: Davies, Mabaya, Chambers, Jones, Elliott, Corness, Frauendorf
Bajcetic, who joined Liverpool from Celta Vigo in December 2020, was not eligible for List B when it came to the group stage.
But the 18-year-old now qualifies having been with the club for over two years.
He can therefore be removed from the Champions League squad and re-registered through List B, freeing up space for one of Gakpo, Keita or Oxlade-Chamberlain.
Space will still need to be made for the other two – or, in theory, any further January signing – with the likes of Arthur, Calvin Ramsay, Fabio Carvalho and long-term absentee Luis Diaz feasible options to remove.
It should be noted, though, that a maximum of three new players can be added to the Champions League squad, meaning if another signing was made in January, one of Gakpo, Keita or Oxlade-Chamberlain would need to be omitted.