While the club have been active in the transfer market, this always increases the chances of having the occasional deal not go as well as they may have hoped.
One particular deal that looks to have been a let-down for the Hoops is their 2020 swoop for midfielder Ismaila Soro.
During the January transfer window in 2019/20, Celtic secured a four-and-a-half-year deal for the midfielder worth £2m from Israeli side Bnei Yehuda.
Overall, the 23-year-old has made just 43 appearances for the Hoops across all competitions, scoring just one goal and providing one assist in the process.
Back in February last year, former Celtic manager Neil Lennon admitted that the midfielder was “struggling with a bit of fatigue” as a result of the number of games he was playing at the time.
This doesn’t seem to be the case this season under Postecoglou, as the midfielder has only started six of the 19 games he’s appeared in across all competitions.
According to Transfermarkt, Soro’s current market value stands at £810k, which is significantly lower than the £2m that the Bhoys splashed out to bring him to Celtic Park.
Given his lack of action in this campaign, it’s hard to suggest that he’s been justifying that transfer fee.
Even when he has been given the chance to play in the league, the midfielder hasn’t done much to convince Postecoglou he has what it takes to be a regular member of the team.
With eight league appearances to his name, Soro has earned himself a rather underwhelming overall WhoScore match rating of 6.25, making him the lowest-rated Celtic player to play in more than two league games.
Taking all of this into account, unless the 23-year-old can turn his fortunes around sooner rather than later and start helping the team out, then the club will start to have some regrets over bringing him to Parkhead in the first place – with his signing already appearing to have been something of a nightmare.