It cannot be understated just how much of an impact Lee Cattermole has had since arriving at the club as a raw - immature, perhaps - dogged central midfielder, brought back to the North East by Steve Bruce, having been his captain at Wigan Athletic during their short stint in the North West together.
I knew from the moment I watched on from the away end at the Riverside back in 2007 as he tried to pull Grant Leadbitter's head off his shoulders that this was a man who played football with his heart on his sleeve.
Cattermole - entering his sixth year as a Sunderland player - has gone from earning a reputation (at least to the wider public and national media) as a 'reckless thug', to proving himself as a battle-hardened, mature professional who is the very core and soul of Sunderland AFC.
Don't get me wrong, he has his flaws.
There is no doubting he's prone to mistakes, but he's human. He's certainly no world beater. What he lacks in pace, height and technique he more than makes up for in heart, passion, raw-belief and work ethic. He's a leader, both on and off the pitch. The fans love him.
The remarkable turnaround he achieved in going from training with Kevin Ball and the under twenty-one's squad to stepping out on the pitch to represent our club in a cup final is one that should never be underestimated. This is a human being who just does not know how to give in.
Sunderland haven't collected a single point without Lee Cattermole in the team since we drew with Swansea last season, a game which finished 1-1 at the Liberty Stadium in February of last year - that is a fact.
Can you imagine a Sunderland without him? I can't. When Paolo Di Canio attempted to alienate him, and he was almost sold to Stoke in 2014, I suspect few envisaged that we'd be sat here two years later talking about him as part of our squad, but we are. I think anyone who believes that we'd still be a Premier League side without his impact in the two years since is kidding themselves. Had Cattermole completed a move to Stoke, we'd almost certainly be playing Championship football right now. I'm one hundred percent certain of that.
It was in that transfer window that Gus Poyet brought Liam Bridcutt to the club from Brighton in order to effectively replace Cattermole, and he was seen off with ease. Whilst Bridcutt now expects his future to be with Leeds United, Catts signed a new contract in the summer - a five year deal - which effectively committed the rest of his career to playing for us. In an era where the good old days of players sticking around and falling in love with a football team are long gone, the likes of Lee Cattermole are a rare breed.
It was a huge relief to me that he didn't pick up a yellow card in the Arsenal cup tie, which would have seen him miss Wednesday's six-pointer with Swansea due to suspension. It'll come, eventually, but I'm thankful that he's able to play in that game. His impact, as previously stated, is crucial to us winning football matches.
The fact of the matter is that we struggle to win games when he isn't on the pitch. Ignorant people will scoff, but any club would be lucky to have someone like him. He embodies everything I love about my club. He gives a shit.
If - big if - we are to stay in the Premier League for yet another season we have to hope Lee Cattermole plays as often as he possibly can. The way we capitulated whilst he was sidelined due to injury following the wins over Stoke and Crystal Palace was telling - similarly, when he left the pitch on Saturday at Arsenal, we fell to bits. I'm not sure what it says more about - the impact Cattermole has when he's on the pitch, or the character of his teammates. Irrespective, he's clearly the heartbeat of our team, and we're much worse off without him.