Based on what he did to Billy Miske in Pittsburgh (write ups are awesome!!) as well as the severe constraints of the black fighter in the Jack Johnson hangover era, as well as the form he shows' on film in his prime, very-very high.
Steve, I have articles from Harry Keck wherein friends and fam recall Harry stating Jeff Smith as the culprit, another where George Engel who managed Harry during this stage of his career pointing the finger at yet another opponent, this clouds the waters considerably in my opinion. I think a better response than my previous..."no"... posted because I was running late, would be, in my opinion as a Greb researcher, I believe it would be damm near impossible to say with any completer certainty who did the deed from what I've come across. Different researchers travel different paths and inevitably come across different information. Perhapse you've found a smoking gun I don't know about? That and I connect Norfolks Billy Miske ass kicking, two times over, costing him dearly getting Dempsey in the ring, as either sparing partner or official opponent. Whenever I read about Miskes tremendous ring prowess I just shake my head. Its yet another measure of Harrys greatness that he fought Kid Norfolk at all, let alone twice.
I agree that it would be difficult to nail down who exactly did what to Harry's eyes but I give more weight to articles published at the time of his death than years later. I also think Miske is overrated today, due largely to his tragic story...
Is there necessarily only one culprit? Stopped only once in over 100 fights, by a prime Dempsey, while he was fading, then never again, getting out of his death bed to leave as a knockout winner over a well conditioned Brennan. (Norfolk was stopped six times, although he did go 5-0 against world champions.)
I am a big Miske fan, and a lot of that is due to his tragic story. What makes me respect him is how he adapted to his tragic circumstances and transformed himself from a technical boxer to a knockout artist, at world level. When I look at the problems that fighters like Jimmy Braddock and Jersey Joe Walcott faced and how it stunted their careers, I see Miske as a verry special fighter.
Until recently I felt that Miske didn't begin suffering from his illness until early to mid-1919, but of late I have become convinced that he very likely begin suffering some initial effects as far back as 1916. He doesn't rank with the likes of Dempsey, Greb, Langford, or even Tommy Gibbons, but he was a pretty fair fighter. He certainly fared much better against Dempsey in 1918 than the other heavyweight contenders Dempsey faced, with the exception of Willie Meehan and that short four-round contest.
I think that he could reasonably be ranked with Tommy Gibbons as a heavyweight despite the fact that Gibbons just seemed to have his number. He probably has the better names on his resume at that weight.