The definition I have found is that linear tv is when most of the audience watches a program in real time at the same time when it is broadcast. Non-linear is everyone bingeing Stranger Things on their own schedule. Some people use linear to mean traditional broadcast networks as opposed to streaming services, but since you can DVR anything, network shows aren't watched linearly any more than streaming services are.
Except sports. At this point, live sports is linear TV, regardless of what kind of platform it is on. You might watch a replay, or time shift a DVR copy, but mostly everyone watches live.
So I still have no idea what Paul Kennedy is referring to when he says linear might be on a different schedule. If he meant occasional games might be on other networks at different times, he should have said so. "Linear or stadium conflicts" is really unclear, as well as arcane jargon.