If you're going to use Greg Cook with the Bengals as was suggested earlier, how about starting with a Cincinnati POD... the Reds traded Frank Robinson. hey needed pitching and he was a bit too old, from what they claimed (there may have been a race element, too, but it was a decent trade at the time, it just turned out awful later), so they engineered a trade to Baltimore OTL. MIlt Pappas was Baltkmore's top pitcher, but in Cincy he wasn't a good fit. But, what if the Orioles don't let go of Pappas and the other hurler they acquired instead, but instead do a swap of Robinson for outfielder Simpson (OTL) and a young pitcher named Jim Palmer. The Reds can throw in some veteran pitching, too, to get the Orioles over the hump after coming so close in the previous 2 years.
The Orioles win the pennant, but only by 2-3 games, and still win the World Series, though perhaps in 5 and not 4, but the big thing is the Reds have that starter I mentioned for the future.
Suddenly, Sparky Anderson, when he comes on board in 1970, doens't have to play Captain Hook with at least one of his starters; Palmer puts up great win totals and his duels with Tom Seaver for the Cy Young remain legendary.
If that doesn't seem as likely (and thinking bck, maybe it isn't - it looks better now but looks worse to the eyes of 1965), then how about this:
The Red Sox lose 2 more games to the Athletics in 1965. Doesn't seem significant, right? But in 1966, that gives them the 2nd pick int he draft. And, when the Mets pass on Reggie Jackson, Boston takes him, despite the calls for a pitcher, because REggie hits amazing home runs and they love sluggers in Boston.
Tony C. gets beaned as in OTL, b ut maybe not as bad; just enough to be out a few months, and then he has been Wally Pipped by Reggie and his home runs in 1967. Tony . is traded after the season, and the Boston outfield going forward is Yaz, Reggie Smith,and Reggie Jackson.
But, more people know about the Robinson trade, and I can see them doing that if the Orioles could convicne the Reds to take a prize young pitcher instead of a veteran. (Or maybe Palmer in place of Pappas but the others going also, and a veteran pitcher going along with Robinson. That might be better.)