It's a special night for Cowan. He will lead the team out at Carisbrook and become just the 15th player in the franchise - and the sixth back - to earn 50 Super 14 caps.
"It's not something I normally get caught up in. But over the last couple of weeks I have thought a bit more about it,'' Cowan said of his milestone".
"I'm very proud to have reached 50 caps for the Highlanders and it's something I'll cherish. It's a great honour.''
Cowan (26) finds it difficult to list a highlight from his time in the Highlanders, which began when he was whistled over to South Africa in 2003 as an injury replacement for Danny Lee and made his debut off the bench against the Cats, who are now the Lions.
Last year, when his form was outstanding and he was named New Zealand Super 14 player of the year, was something special. But, when pressed, Cowan plumps for his first start in a 39-8 thumping of the Reds in Invercargill in February 2004.
Cowan is now a senior player in the Highlanders, and it hurts him to reflect on the team's record six-game losing streak to start the season.
"It's been difficult for me because six losses on the trot... I mean, I was certainly not thinking that was possible at the start of the season".
"But it's happened. The big thing is we can't get down on ourselves. Guys are still turning up with a smile... and that's great to see".
"I know I'll be going as hard as I can on Friday night and giving the body no respect. We just have to win. It's as simple as that".
It hasn't seemed like Cowan has come close to matching his form of 2007 this year.
While he admits he started the season a bit slowly and made some unusually basic errors in the loss to the Chiefs last weekend, he describes himself as happy with his form and believes he is getting better each week.
No doubt Cowan and some others in the Highlanders might be getting more positive press if they had won a few games. But Cowan is not bothered at the thought his team's poor record may hinder his chances of an All Black recall.
"I can't look down that road. I honestly can't worry about it because those guys who pick the All Black team are the ones who decide whether you're up to it.
"I've just got to worry about the Highlanders. My sole focus is helping the team get their first win. All my focus and all my energy is going into that.''
The perception in Southland appears to be that it is an indictment on the Highlanders that it has taken 13 years for a Southland player to reach 50 caps.
Cowan has been one of the most valued Southland players - tonight will be his 44th start out of 50 - and despite speculation he had considered leaving the franchise, he said he was a happy Highlander.
"In the middle of last year I had to sit down and sort out what I was doing with my future, and I decided to commit to New Zealand rugby and to the Highlanders and Southland".
"I'm very happy with where I'm going. I've got no qualms about staying here because I enjoy it totally. I've enjoyed being a Highlander a lot in the last couple of years.''
It is impossible to over-emphasise the importance of this game to the Highlanders.
They are past the stage of dreaming of a top-table finish but can no longer be satisfied with bonus points. This is a virtual final and they must take a win-at-all-costs attitude into it.
With a home game against the unbeaten Sharks next week, then a three-week trip to South Africa followed by games against the Blues and the Crusaders, the opportunity to beat one of the lesser teams must be taken.
The Lions are similar to the Highlanders - low on star power but high on grit and pride.
They have big forwards and a talented pair of backs in halfback Jano Vermaak and fullback Louis Ludik, and have been good enough this year to beat the Cheetahs and get close to the Force.
This is desperation time for the Highlanders, though. This might not shape as an entertaining clash but if they win they won't care.
