The Johannesburg franchise started the URC in positive fashion, earning four wins out of their first five games, including an eight-try mauling of Edingburg in front of the Emirates Airline Park faithful.
But the rigours of stretching a squad and travelling over two tournaments - the URC and the Challenge Cup - began to take their toll. The Lions were bundled out in Round 16 of the Challenge Cup in April, but their form had already begun to wane in the URC, especially on the road. They only managed two away wins in the URC this season.
The Lions are coming off the back of a disappointing loss at home to the lowly Scarlets, effectively ending any hopes of a top eight finish. They are wallowing in 13th on the URC table.
"It's a huge disappointment [missing the play-offs]," van Rooyen told the press.
"We set our targets and goals on it. I feel we started off well enough. It's always tough between January and March when you're bouncing between two tournaments with vastly different conditions and challenges. We felt we were in a position to get ourselves there. Just one too many results went against us.
"If we scored the fourth try last week [against Connacht] we were in the hunt to be seventh or eighth place on the table. That's how small the margins are.
"If we scored those two [disallowed] tries against Cardiff, which I still believe were tries but there wasn't enough video evidence to prove that it was scored.
"We potentially could've still have ended fifth or sixth if you add those points. That's how small the margins are and what makes this such a great competition.
"It's double zero point one percent in every aspect of the game. It's great for a spectacle. Obviously, we're not consistently good enough to be there yet.
"There is a lot of learning for us as a group and as individuals. I don't like to say we are currently a young team because of a couple of the senior guys that are injured."
The Lions will attempt to salvage some pride when they host Welsh outfit Ospreys in Johannesburg on Saturday.