‘What ifs’ are commonplace in sports, particularly in the world of association football.

In many instances, it can boil down to a transfer that failed to transpire or materialise, or simply that the timing was not right between a player and club at any given point. Quite ironically, David Turnbull’s Celtic story seems to fit into both categories, given the nature of the two parties’ near-five-year connected relationship.

The Scotland international will leave the club to join Cardiff City in the Championship. A disappointing way to bow out, especially considering the buzz that surrounded the player when he joined the club.

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Of course, his arrival in 2020 under Neil Lennon does not tell the whole story, as he was very publicly courted by his future employers the season before. Following a breakout season at his boyhood club Motherwell where he scored 15 goals and assisted a further six, Celtic entered a lengthy negotiation process with the player and his club concerning the young star’s availability.

After statements from Celtic, Norwich’s attempts to hijack the bid and a fully-fledged saga emerging concerning Turnbull’s future, a fee was agreed between the two clubs. Interviews were filmed, all the regularities were sorted, and it looked like Celtic had a new dynamic midfielder on their hands for the 2019/20 season. That was until Turnbull’s medical flagged up an issue in the player’s knee that required a minor operation. Celtic tried to renegotiate in light of this development but talks collapsed and Motherwell’s number 28 remained at the club, undergoing an operation to correct his injury in the process. He returned to Motherwell’s first team the following February and re-established himself leading up to the league’s curtailment due to COVID-19’s escalation in the UK.

The beginning of Motherwell’s 2020/21 season saw Turnbull front and centre of everything positive about the Steelmen, so much so that Celtic decided to submit a bid for the player, over a year after the midfielder’s move to the Scottish champions was ruined by injury at the last step. Joining Celtic as they geared up to try and win the elusive ’10 in a Row’, Turnbull was viewed by many as potentially being the goalscoring midfielder that had been missing since Stuart Armstrong had left the club.

Speaking to Celtic TV, the 21-year-old was ecstatic to finally get the deal over the line. He said: "I'm absolutely delighted to be here, especially after what happened last year, and I'm ready to hit the ground running. I feel I've started well this season and I want to carry that on with Celtic.

"It's great to join the biggest club in Scotland and I want to help us win more silverware in what I know is an important season for Celtic."

As we all know by this point, that ‘important’ season for Celtic turned into a nightmare for the club, despite securing an unprecedented ‘Quadruple Treble’ that winter. In what was a disastrous campaign both on and off the park, Celtic lost the league by 25 points and failed to defend either of their domestic trophies, as Rangers and St Johnstone won the Premiership and League/Scottish Cup double respectively.

Despite this, there was one shining light that illuminated the darkness that was Celtic’s title bid during the height of COVID-19, and that was the emergence of Turnbull as a first-team regular under the struggling Lennon. Not an automatic starter until midway through the season, Turnbull found most of his initial minutes coming off of the bench as a substitute, not helped due to catching the virus shortly after arriving at the club. It may have been a dead rubber, but Celtic’s 3-2 win over Ligue 1 side Lille in the UEFA Europa League was Turnbull’s breakout game, as he scored the winner on the night to cap off a standout performance from the promising midfielder.

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From this point, Turnbull was essentially a first-team option for Lennon, as the season unravelled around him and his teammates. He would score nine goals and contribute eight assists in his debut season for the club, as he scooped both Celtic’s player and young player of the season for the 2020/21 season. A very positive start to life at Celtic, which had many believing that the only way was up for the promising attacking midfielder.

That belief continued into the following season, when Ange Postecoglou was appointed as Lennon’s successor at the club. An ever-present under the Australian in the first half of his first season in charge, Turnbull would injure his hamstring during the League Cup final, which would turn out to be a very costly casualty for the player in hindsight. Celtic went on to win the trophy 2-1 on the day, with Kyogo Furuhashi scouring a double as the side picked up their first piece of silverware under the new manager. Looking back on the footage of the celebrations that day, Turnbull was front and centre of the festivities, even though he was in crutches!

Returning to full fitness in March 2022, the team he reintegrated into was very different to the one he departed, thanks to Celtic’s business in the January transfer window. On Hogmanay, the club announced the triple signing of Daizen Maeda, Reo Hatate and Yosuke Ideguchi, the latter pair both being midfielders. Midway through January, Turnbull’s task was made even greater with the arrival of Matt O’Riley from MK Dons. By the time the injured talent had returned to league action, he was already playing catchup to Hatate and O’Riley, who had both set the heather alight since joining.

He would play a bit-part role from then until the end of the season, as Postecoglou elected to go with his new acquisitions rather than the midfielder he entrusted just a few months prior. In spite of this, he still played his part in delivering two trophies for the club under the guidance of the now-Tottenham manager, scoring 10 times and assisting a further eight in 42 appearances in all competitions.

Turnbull would put up similar numbers in terms of appearances for Celtic the following campaign, as Celtic went on to win the eighth treble in their history. Making 38 in total, his numbers dropped to only five goals and seven assists in this period, as Postecoglou preferred the midfield trio of captain Callum McGregor, O’Riley and Hatate, as well as Aaron Mooy, who signed that summer from Shanghai Port. Only making nine starts in total that season, the writing perhaps was on the wall for Turnbull, especially given his contract only had a year left to run. Fortunately for him, the bright lights of the English Premier League attracted Postecoglou, which led to the return of Lennon’s predecessor in Brendan Rodgers. Could this be the manager that reignited the undoubtedly talented midfielder’s future at Celtic? Or would the final roll of the dice be an unlucky one for Turnbull?

The early signs looked promising, with the player starting in place of Hatate, which was a shock to many. Scoring a brace on Flag Day against Ross County, Turnbull looked to be a man back in favour in the starting line-up under Rodgers. Following this standout performance, his manager praised him but issued what was required if he was going to make the grade under him at Celtic.

He said: “I spoke to him in pre-season and told him it would be a shame if you don’t achieve what you can do at a club like this, because you have the talent, but you have to be a working talent, and you have to be able to run and be aggressive in your game. If you can do that, then your qualities will come through.”

He started the next match, an away trip to Pittodrie to face Aberdeen, again preferred ahead of Hatate in Rodgers’ first team. Unfortunately for Turnbull, however, his inconsistency struck again, and he found himself subbed off at half-time. Hatate came on in his place, and before getting injured, he showed the levels of old for 25 minutes, before getting replaced by Odin Thiago Holm himself. Perhaps a lucky opening for the Scottish midfielder?

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In truth, his appearances from the off this campaign have been sporadic, with the player only named in nine starting line-ups. Despite having no assists, He has managed seven goals in his 19 total appearances, with the midfielder adept at scoring a mixture of long-range strikes and penalties, the latter being a real area of weakness at the moment.

This brings us full circle, Turnbull’s time at the club is now up. The now-24-year-old will move on to pastures new down south in the Championship with Cardiff. Thanks to his consistent numbers at Celtic – in both goals and assists – he should be able to hit the ground running with his new club. You only have to look at examples in the recent past of Teemu Pukki and Ryan Christie forging very good careers for themselves in the same league after leaving the Scottish champions.

Still, Turnbull’s Celtic career will no doubt be looked back on as one of slight disappointment, as he did not hit the dizzy heights that were expected of him at the club, particularly after his debut season. Here’s hoping he manages to kick on and potentially become that player, though it won’t be at Celtic, unfortunately…