In the pantheon of great Celtic defenders, Kelvin Wilson may not make everybody's shortlist or immediately spring to mind. When it comes to discussing players who graced the green and white, Wilson remains one of Celtic's great 'what ifs?'

Signed by Neil Lennon from Nottingham Forest on a pre-contract agreement back in June 2011. Wilson's two-year stay at the club was indeed brief but there were some wonderful highlights along the way. The elegant stopper's Celtic career yielded two Scottish Premier League titles and a Scottish Cup. He was also part of Neil Lennon's Celtic side that downed the mighty Barcelona on an unforgettable night in the Champions League at Parkhead in November 2012.

Homesickness and family ties led to Wilson leaving the club in the summer of 2013 just as he had enjoyed a stellar season in Glasgow. There are questions which will always remain when discussing Wilson and Celtic: What if Wilson had stayed longer? What could the player have achieved?


The Celtic connection & signing for the men in green and white

Despite not growing up a Celtic supporter it was Wilson's best friend Leon Best - whose mother was Irish - who educated him in the ways of the Scottish side. Wilson fondly recalls how Best's bedroom walls were awash with Celtic posters and memorabilia. Even being a diehard Nottingham Forest supporter, Wilson understood back then that Celtic were a big deal.

Wilson said "My best friend in football when I was growing up was Leon Best who went on to play for Newcastle United and as kids we were inseparable. His mum was Irish, so I was well aware of Celtic. We used to stay over in each other's houses and his bedroom was full of pictures of Celtic players. I remember he had this massive picture of Regi Blinker on his wall. I don't know why. I was well-versed in how big a club Celtic was."

Had the fates intervened sooner then Wilson could have found himself taking the journey north of the border during Gordon Strachan's tenure as Celtic boss. Lennon had got to know the player rather well as he enjoyed a sojourn at the City Ground before calling time on his playing career. Lennon recommended Wilson to Strachan and despite Celtic embarking on a few scouting missions nothing ever came of the reputed interest. When Lennon finally returned to take over Celtic as reserve team coach before landing the managerial reins, the Northern Irishman made Nottingham one of his first ports of call to solidify Celtic's defence.

Wilson said:  "I was having a decent spell at Nottingham Forest and it was Lennon who mentioned my name to the Celtic manager Gordon Strachan at the time. Lenny was at the end of his career at Forest and he liked me as a player. We had the youngest team in the league and he came in at 37 and he was the senior pro and we just hit it off straight away and we got on well.

"He liked the leadership qualities that I had as I was one of the few who had run-ins with him on the pitch and we'd both tell each other to 'f**k off' and he liked that about me. I think he saw a bit of himself in me which was a decent compliment Lenny ended up leaving and I stayed at Forest for another three years and whilst there was interest from Strachan back then nothing came of it.

"Lenny told me he had given me a glowing reference to Strachan. Celtic sent a scout to watch me for a few games but nothing materialised and then Lenny got the reserve team post and then the manager's job at Celtic and he was back onto me. I remember Nottingham Forest was playing Newcastle United at St James's Park and I saw Lenny walk by the window of the team bus. He looked at me and winked. My agent then let me know that Lenny was extremely keen and that he wanted me to sign for Celtic."


Playing for Celtic and the goldfish bowl mentality

Wilson recalls that he had a period of adjustment in his first season at the club as he knew nothing about the Glasgow Goldfish bowl mentality and what playing for a massive club like Celtic entailed.

The boy from a tough council estate in Nottingham soon realised that even he was in for a rude awakening both on and off the park. Wilson said: "It gets frustrating trying to explain to people just how big Celtic are as an entity and a club.

"You can't just win a game 1-0 at a club like Celtic. I remember when we squeaked a game 2-1 and I was thinking at least we'd won the match. We got slaughtered in the papers and I had just signed and that was the first time I realised that you had to play 'The Celtic Way' so to speak. I was thinking 'Wait a minute, we've won the game' but that was not enough. The difference between just winning the game and playing 'The Celtic Way' was a massive thing for both the fans and media alike.

"The whole goldfish bowl of Glasgow was another thing that was a new experience for me. I keep myself to myself and I have a very low social media profile as that's the way I like it. I don't thrive off attention that way and that was a massive shock to the system. Going for meals was difficult as fans would always want to talk and I totally understand that as I was a football supporter too growing up and some people just get starstruck at times. It took a bit of getting used to, let me tell you!


The Real Madrid breakthrough and homesickness 

Wilson readily admits that his first season with Celtic was interrupted by injuries and that by the start of the second campaign he was making plans to quit the club due to family ties back in Nottingham. It was Lennon who persuaded him to stay and he was glad that he did after a breakout performance against Jose Mourinho's Real Madrid in a glamour pre-season friendly in Philadelphia in the summer of 2012.

Celtic lost 2-0 but Wilson has set a high personal bar which Lennon purred over and convinced him that his best days in a green and white jersey were still to come. He wasn't wrong! Wilson said: "I had two great years at Celtic. The first campaign was interrupted by injuries but I played some of the best football of my career in the second season at Celtic. The second season was the highlight of my career because of the calibre of players I played alongside and the teams that we played.

"Players need to find their feet with clubs and the one thing I did learn at Celtic was that when you are happy you play your best football. When you have stress that can affect the way do your job. In my first season, I had just become a father to a child back in Nottingham and  I was travelling back and forth all the time. So, there was some personal stuff going on in my life and it was hard to fully concentrate on the football and then add the injuries into the mix that first season was tough at times. I was close to leaving for Leicester City after the first season but I am delighted that it didn't happen.

"Lenny was constantly telling me to persevere and that it would click and he said to me that I was good enough to make it at Celtic. We played Real Madrid in a glamour friendly in Philadelphia in the USA and at that point, I was still actively trying to get a move back down south. After that match, Lenny created a big fuss and a scene and told me I was unbelievable and that I had set the standard for myself and he was right as my Celtic career took off right there and then.

"I don't know what it was if it was confidence or whatever, but I realised that I could hold my own at a club like Celtic and I never looked back after that. Game after game, I just got better and better and it got to the point where I knew I was playing every week. What I also learned playing for Celtic is that it is every team's cup final. You look at the FA Cup and you see non-league and lower league sides raising their games to knock out teams higher up the pyramid than them. Those shock results happen because it is a one-off occasion but playing for Celtic is like that every week.

"You constantly have to peak and produce to the highest standard. It is a massive thing for Celtic players. Even playing in Europe against the so-called bigger teams it didn't matter at a club like Celtic you are expected to perform and not only that you are expected to win as well."


Encountering the nice nutter Scott Brown!

Wilson revealed that he didn't know what he was letting himself in for when he joined a Celtic dressing room full of loud voices and real characters. Lesser players may well have been intimidated by the thought.

He recalls how he had watched TV footage of Broony and wondered if his quieter personality would clash with the more garish Celtic skipper. Whilst Wilson was no wall flower he needn't have worried as Broony and him struck up an awesome friendship. Wilson said:  "I remember going into that Celtic dressing room and I had watched some of the games before I joined. I studied Scott Brown in-depth and my initial reaction was: "Oh God, am I going to get on with this guy as he looks like a nutcase!"

"Nothing could be further from the truth as Broony is one of the nicest guys I have met in football. He is the best captain I have played under. He is the most humble and great guy despite what he has achieved in the game. The Celtic dressing room back then was full of great guys but even better characters. Lenny bought the best in British back then with the likes of myself, Joe Ledley, Adam Matthews and Gary Hooper to name but a few.

"The manager got the balance spot on and the blend was good as he filled it with a lot of British-based players, which worked wonders for Celtic."


Barcelona, the pre-match premonition and all that

Only one man genuinely believed that Celtic would beat Barcelona in the Champions League in November 2012. That man was Wilson, as Kris Commons will testify.

Wilson insists to this day that as the Celtic supporters unfurled the banners celebrating their 125th anniversary and the atmosphere took hold he was gripped with a feeling that it was going to be one of those special nights on the European stage. Wilson said: "I will never forget that Champions League night against Barcelona.

I stand by what I said to Kris Commons that night and I truly believed that Celtic were going to beat Barcelona. Kris will back that story up and vouch for me that I did say that. It was in the warm-up, and we didn't have Scott Brown or Gary Hooper in the team. I was just jogging across the pitch and stretching and I told Kris I had a great feeling about the game. His response to me was: "F***ing hell, I hope so!"

"It was just a gut feeling and I felt that if everyone inside the stadium felt like I did then we would win. That night was everything that was wonderful about Celtic and why you can never predict the outcome of a game of football. I had family and friends come up for this game and one of my best mates is a season ticket holder at Manchester United and he swears to this day that it is still the best atmosphere he has ever experienced at a game of football. Hands down Celtic beat one of the best sides to ever play club football and every player played their part that night.

"I remember Lenny saying in his team talk that Celtic needed at least a nine out of 10 performance from every player. An eight wasn't going to be enough and he got it. That is what happens when you have a team spirit and camaraderie and a dressing room like ours. I won two Scottish Premier League titles and a Scottish Cup with Celtic and they are prized possessions. A lot of players play in English football and don't win any silverware and that was one of the main reasons why I wanted to come to Celtic to win trophies and play in Europe for such a huge club.

"People ask me what are the proudest moments of my career and it is winning those Scottish titles and the Scottish Cup with Celtic and having those winners medal draped around your neck I also got to experience Champions League nights like that one against Barcelona. It was incredible."


Leaving Celtic

Wilson's time at Celtic may have been short but it was sweet. That's why there is no bitterness about the circumstances which brought about his departure. The stopper was sold back to his boyhood club Nottingham Forest in the summer of 2013 for a fee of around £2.5 million just after he had enjoyed the best season of his career.

Despite Lennon's pleading with him to stay for another 12 months to secure a safe passage back to the English Premier League the Celtic boss knew he was fighting a losing battle as family matters won in the end. Wilson said: "I only left Celtic for family reasons in the end - why else would I leave such a massive club?

"I don't think Lenny fully believed me or fully understood at the time that I would want to leave Celtic but he did in the end. I remember Lenny having a conversation with me and he told me to stay on at Celtic for another year if my dream was to play in the English Premier League. My dream wasn't to play in the English Premier League. I love football but that wasn't my dream. Then Lenny said Celtic would offer me a bigger contract with more money and again it wasn't about the money. Lenny finally realised that there were bigger things in life for me regarding family issues as I just wanted to go back home.

"I still look out for Celtic's results and I follow them as I am still in a couple of group chats with Gary Hooper, Joe Ledley and Kris Commons and I see them whenever we play the Legends games. It is always great to catch up with them. Once you have played for a great club such as Celtic, and had a small part in its history, then I think you have an affinity that will never leave you. It’s hard to put into words.

"If I could sum up my time at Celtic I would say it was successful, a pleasure and a dream come true."