I think he would have been a force to be reckoned with in that era, but James J. Jeffries would have been a hard hill to climb for him. I do believe he would have had a good chance of lifting the title from Bob Fitzsimmons if he had gotten to him before Jeffries.
Given three months of modern preparation, and only two warm pints of ale a day, I would pick John L over Lennox Lewis.
Does he get his two warm pints of ale, on fight day, before, after, or DURING the fight? That could be the deciding factor here.
Assuming that you keep all of Sullivan's stats,skills while giving him knowledge of the modern era, plus him adjusting his skills to fit more to the era,I think he'll fit just fine.
That's easy, because of his sheer dominance. All you would have to do is argue that his opposition was good, or even that they weren't all that bad. The problem with that is that the limited evidence points to them not being that good.
He might not have even been relevant. Sullivan after 1885 just wasn't better than the top HWs and to whatever extent he could have still succeeded he would not have been the dominant figure he was but one of many. Goddard was the same age as him and I don't think Sullivan was as good as Goddard but even if he was Goddard wasn't a dominant figure he won a disputed title at nearly 40. Making Sullivan(or Goddard) 5 years younger would help a little but Sullivan basically stopped fighting at 28 his age wasn't the main thing holding him back here. Making him do a little better against the top guys doesn't help when he didn't fight them. Just look at the record of top guys Sullivan did fight(Mitchell, McCaffrey, Herald) against ones he didn't from the following era. Throw Cardiff and Kilrain(who Sullivan beat at bareknuckle) in there even Corbett it gets a little better but not much. Most of the success of Sullvan opponents is against other Sullivan opponents especially those Sullivan beat. 31 of Sullivans 37 wins were against guys without multiple wins and 28 of those were debutants. Imagine how Wilder or anyone today would be treated if he pulled this bleep? Y'all joke about Luis Ortiz but Jimmy Elliot was born during the Van Buren administration when Queen Victoria wasn't 21. Elliot was 6 years older than the Marquess of Queensbury. Fitzsimmons. Jackson, Slavin, McAuliffe, Goddard, Killen, Denver Ed Smith, Godfrey, Lannon, Billy Wilson, Gus Lambert and Ashton are guys Sullivan didn't fight during his 5 year break who'd have had a decent chance of beating him. If we make Sullivan 5 years younger now we just are adding more names to that list.
Look, Sullivan started drinking by 1883 and by 1884 he was a drunk ... his prime was 1881 and 1882 ... Spot on ... he was a drunk after 1883.5 .... the whole thing is silly .... he was a highly charismatic natural talent in a transition period that never transitioned ... could he have if he trained, was trained properly over years , sure .. but in reality his autobiography describes him properly ... A 19th Century Gladiator. The way Janitor endlessly and will again after he sees this make an argument that he was an established and creditable M of Q fighter in any way close to those that immediately followed is romanticizing ... he was the last of his breed.
Honestly don't believe anyone who claims they've read heaps papers and contemporary sources and believe John L was more than hype.
There wasn't anybody else of much importance in the heavyweight division between 1882 and 1889. If that is not a dominant champion, then there is probably no such thing as a dominant champion.
The thing with Sullivan is if any other champion had any of the other problems he had they'd get called out for each and every one of them The legion of debutants Getting knocked down by a WW who was not Bob Fitzsimmons Vanishing with the lineal belt for 5 years after the Cardiff fight His few good opponents poor record against other good HWs. Lack of power feats and all his major stops except Mitchell being given to him by the cops I'll be a little more generous to Sullivan in that the early 1880s he probably was the best Queensbury fighter and he was a top fighter for awhile. Sullivan v Mitchell in 1883 is the right place to start the Queensbury lineage. Kilrain, Mitchell, McCaffrey were fine names in the early 1880s the problem is he tried living off those names until 1892. Corbett was mostly living off those names into the 20th century. Janitor I find incredibly credible on most other topics. Hes one of the few whose scholarship makes regularly visiting this site worthwhile.