Kearney misses out on the two-game tour after an unlucky hamstring injury during his side's 37-9 bonus-point victory against Cardiff Blues last week.
"Any injury is tough, but you get used to it throughout your career — missing games for Leinster, missing games for Ireland, you know," he says in the latest edition of Hot Press, which is out now.
"The last time I watched the Lions without having been a part of it was twelve years ago. So it was pretty tough. It is the pinnacle of a player’s career to get selected for the Lions. But you just turn into a supporter and cheer them on."
He reveals that the lowest point in his career was injury-related. "In 2011, I was out for nine months. I missed a huge amount of rugby. Leinster won the Heineken Cup. It’s fantastic watching your own team win trophies, but knowing you’re not a part of it can be tough."
He adds, "I have learnt over the last number of years that there are so many different variables that can determine your future — injury, selection, contract lengths.
"My sole priority at the moment is to get my body in a really good place that I’m fit and I can play games on a week-to-week basis.
"Long term, I’d like to get to another World Cup. But there’s so much that could happen before then."
Kearney has been Audi ambassador for several years now and also speaks about his love of cars in the new Hot Press. "You always fear getting into an accident, don’t you? But they are safe cars and I’m a good driver, I think. I don’t worry too much about it," he tells our writer Anne Sexton.
You can read the full interview in the latest edition of Hot Press...