Big early influence. One of the first, actually. But I have a story! At an outdoor drum show in L.A., I can't recall what it was or where, only that it was out of doors, I noticed him standing with a circle of guys talking and getting autographs. So I walk over and wait until I can get a word in. And when I could, I asked him what album they were at. And he didn't seem to understand, so I repeated myself clumsily, like "what number album are you guys at now?" and he says "18" and I said something very close to "wow, that many! I have the first three ..." and before I could tell him what a big influence he was he gave me the stink eye and turned to someone else. I was mortified.
That is very unfortunate! I never had much contact with him while he was still with Chicago, even though I attended every concert they had relatively close to me from as far back as 1972 (While he was in the band). I have had many interactions with him for the last 15 years or so. Every time, he could not have been nicer, more assessable, appreciative and humble! Other than possibly my dad, certainly my biggest influence and favorite drummer!