Celtic may already be thinking about what they are going to do when the January transfer window opens for business after a difficult start to the season.

12 matches into the campaign, the Hoops have already been knocked out of the Champions League, lost twice to Rangers, and lost their first game of the league phase of the Europa League.

Too many players have let Martin O'Neill down on the pitch and their futures may have to be considered ahead of the next transfer window opening.

One of the players who has struggled at the start of the 2026/27 campaign for the Scottish Premiership giants is Sebastian Tounekti, who joined the club last year.

Where it's gone wrong for Tounekti

Brendan Rodgers signed the Tunisia international from Hammarby for a fee of £5m and he enjoyed an electric debut against Kilmarnock, completing five dribbles and creating four chances for his teammates.

He excited supporters with his direct play and impressive close-control as a dribbler, bursting past full-backs with ease, but was unable to build on that early excitement.

Tounekti went on to only score two goals and provide two assists in 27 appearances in the Premiership for the Hoops, which shows that he did not add enough consistency with his end product to go along with his dribbling skills.

His struggles have continued in the 2026/27 campaign with a return of one goal and no assists in 13 appearances in all competitions so far this season.

What the future holds for Tounekti

Because he has failed to build on his early promise at Parkhead over the past 13 months or so, Celtic may have to part ways with the Tunisian forward when the January transfer window opens.

Tounekti has had ample time to show O'Neill that he has what it takes to be a reliable and consistent performer for the Hoops moving forward, but he has been unable to do so.

The Norway-born forward has played 57 times for Celtic in all competitions and has only contributed with six goals and four assists, which shows that he has not offered consistency as a scorer or a creator of goals.

Therefore, O'Neill should be looking to part ways with the winger, who is valued at around £4.2m by Transfermarkt, to make room for a new addition on the wing ahead of the second half of the campaign.

Who needs to leave alongside Tounekti

Tounekti, though, is not the only underperforming Celtic player whose future could be thrown into doubt when the January transfer window rolls around.

As well as the Tunisia international, O'Neill should also be looking to move on a player who is worth even less to the team as an asset.

Luke McCowan, who is valued at £1.3m by Transfermarkt, is another underperformer who should be on the chopping block after just 12 matches in all competitions this season, due to his struggles since the start of last season.

The Scottish midfielder enjoyed a strong first season at Parkhead, scoring seven goals and providing nine assists in 41 games, but his form since then has left too much to be desired.

This season, for example, McCowan has not played a single minute in five of the club's 12 matches in all competitions, and has produced one goal and no assists.

His struggles in the 2026/27 campaign come off the back of his four goals and three assists in 42 matches in all competitions last season, including just one goal and one assist in 30 Premiership games.

McCowan has not offered consistent quality as a scorer or a creator of goals as an attacking midfielder since the start of last term, and now finds himself slipping down the pecking order and struggling for minutes on the pitch.

Therefore, Celtic should put him up for sale when the January transfer window opens and attempt to move on from him and Tounekti in the same month.