Ok he had already wiped out the divisions best, champion Liston ex champ Patterson contender chuvello paper champ Terrell as well as Europe’s best cooper London and mildenburger . He was almost marking time beating 1950’s contenders and ex Liston victims Williams and Foley. Was there anyone left to fight before his exile? Who does he fight in 68 and 69? Too early for the next generation Frazier Ellis and Quarry or not?
A rematch with Floyd was scheduled in 68. So 68: Patterson, Frazier, Quarry 69: Mac Foster, Ellis, probably Frazier rematch
Leotis Martin seems to be the only guy he missed in that timeframe. He went 2-2 in ‘68 and had a nice undefeated run in ‘69 ending with his win over Liston in December. Unfortunately he retired after Liston with a detached retina, which was career-ending at that time (surgery to correct it didn’t come around until years later).
Probably everyone who participated in the 1967—68 elimination tourney plus Joe Frazier and Buster Mathis. Any further than that would depend on how active he chose to be and who was available. He beat both Zora folley and Ernie Terell In early 1967 with most of the year left to go. I imagine by 1969 quality opponents would have grown slim
There have been rumours that he was supposed to fight either Bonavena or Thad Spencer after Folley, but he said himself, right before refusing induction, that a rematch with Patterson was next. So let's say he does that and then closes out the year with fights against Spencer and Bonavena, what's left for 68-69 is then basically Quarry, Frazier, Ellis and maybe a rematch with Chuvalo. So I'd expect those to be his main fights, perhaps with some fillers like MacFoster, Mathis, Ramos etc. If Ali beats all those guys there wouldn't really be any obvious challenge until the rise of Foreman, and Norton being the banana skin in this scenario as well.
In April of 1967, a rematch was scheduled for Muhammad Ali vs Floyd Patterson, that was scrubbed especially since Ali was in trouble with the U.S Government for refusing military induction, Ali had been stripped of his title and boxing license. Ali had also signed for a title defense against Oscar Bonavena on May 27 1967 in Tokyo, Japan, that fight also had been scrubbed as well. Let's suppose Ali defeats both Patterson and Bonavena, he probably would have in my estimation, his next fight would have been against either Leotis Martin or Thad Spencer in late 1967, Ali stops Martin late, then stops Spencer in round 9. Ali after the Folley title defense on March 22 1967 had mentioned Buster Mathis and Eduardo Corletti. My guess it would be Mathis on March 4 1968 as a tune up for undefeated Joe Frazier. After an entertaining bout, Mathis runs out of steam against a fleet footed Ali, Ali stops Mathis in round 13. On Sept 14 1968 Ali steps into the ring against challenger Joe Frazier in Frazier's hometown of Philadelphia, the undercard is Ali's sparring partner Jimmy Ellis vs Floyd Patterson. A very aggressive Frazier makes a really good show of it, but cannot cope with the speed, reflexes and incredible stamina of the the fleet footed Ali, the champion retains the title with a unanimous decision, Ali tells Joe afterward, I Will Give You A Rematch Anytime You Want One. This is a learning experience for Joe who took this fight despite the objections of Yank Durham. In February 1969, Ali defends his title with a TKO 6 over an overmatched challenger Jerry Quarry. throughout the year, Ali defeats former sparring partner Jimmy Ellis by TKO 12, Mando Ramos in Mexico, City. Meanwhile Frazier is racking up victories left and right. Ali continues with title defenses against Gregorio Peralta, then in June 1970, Ali stops undefeated George Foreman by TKO 10, then in Sept 1970, Ali goes 15 with Mac Foster, the champ retains by unanimous decision. In Dec 1970, Ali stops a game Bob Foster by TKO 8.Then Joe Frazier and Muhammad Ali sign for the anticipated rematch in Madison Square Garden on March 8 1971. Frazier having improved his skills, tired of Ali's rhetoric toward him, finally catches up to the Butterfly, who is no longer Stinging like a Bee. Joe pounds out a fair and square unanimous 15 round verdict to capture the World Heavyweight Title.