The 33-year-old loose-head is in his 16th season in Llanelli having made his club debut back in December 1999.
And with last season’s PRO12 finalists Glasgow on the road to Parc y Scarlets, John is hoping to roll back the years and claim a crucial victory.
He said: “It has come around quickly in the last three or four seasons, it only seems like yesterday I was playing my 100th and 200th game. To make 300 games for the Scarlets, I am happy with that.
“Over the years the Scarlets have been renowned for breeding backs, but we have got plenty of young front-rowers coming through.”
“It is a game we need to target to take a scalp of a top-four team and try to climb into the top four ourselves before the next round of European matches and then the derby games. This block of matches basically defines your season.”
Glasgow have made a red-hot start to the PRO12 season with six wins from their seven matches. But their one defeat came away from home against Ulster, who the Scarlets drew with in round one.
Flanker Aaron Shingler is set to reach a milestone of his own when he runs out for his 100th game. And the Scarlets have been boosted by the return of Rhys Priestland, Scott Williams, Emyr Phillips and Rhodri Williams – who have been released by Wales.
John added: “Over this period when international players are away, you need depth in your squad. We are without our Wales internationals, but we have got to play like we did against Zebre when we were in the same situation. Glasgow are also missing their Scotland players, but looking at their squad, it doesn’t matter who plays or who is missing, they will be strong.”
