Neal McDonough is weighing in on Kevin Costner‘s “Yellowstone” exit — saying it really was just bad timing … although, he notes the issue is between KC and Taylor Sheridan, which seems to hint at something deeper.

We talked to the ‘Yellowstone’ actor — who starred opposite Kevin on the hit show for a handful of episodes back in the day — and he told us on “TMZ Live” Friday that Kevin isn’t BS’ing when he says there were scheduling issues that forced him to bounce.

Take a listen … Neal explains that Kev was, in fact, busy for his new western movie ‘Horizon’ — and because the last season of ‘Yellowstone’ took a while to get going in terms of production … it was ultimately impossible for the leading man to stay on.

Kevin himself has said this … but there have been persistent rumors that there was bad blood between himself and Taylor — who’s the creator and showrunner for ‘Yellowstone.’

NMD doesn’t confirm that here explicitly … but listen to how he characterizes Kevin and Taylor’s  relationship — from the sounds of it, they may not have seen eye to eye.

In any case …  Neal’s got nothing but good things to say about Kevin — whom he says made ‘Yellowstone’ what it is … and credits him with spurring a new interest in Westerns.

He also considers KC to be among some of the greatest actors ever … if not the GOAT.