What is with the stunt double during the fight scenes?

The man they hired to do the stunt work in Cheyenne's fight scenes is much smaller than Clint Walker and, while he does vaguely resemble a relative, it's quite obvious that he is not Walker himself. He's like a reverse Incredible Hulk. He shrinks when he's provoked.

I've seen him in the episodes Home is the Brave, about a bigoted town's refusal to allow a half-Sioux war hero to be buried in their cemetery, and Outcast of Cripple Creek, an episode involving a town divided by Peace Street and Cow Street. I'm sure he's appeared in several other episodes, but I'm still rather new to the series.

In Outcast, there may have been call for a stunt double. Fists were flying and I seem to recall a spot in which he had to dodge a wrench. In Homes is the Brave, however, the was really no call for a stunt man. His opponent locked him in a bearhug, clubbed him across the back, and landed a punch to the midsection. His only other punches were blocked. There was really no call for a stuntman as there was never a point in which they could have accidentally struck him. Was Clint Walker too bulky to throw a punch at the speed which they wanted? There really wasn't any reason I could see for the smaller stunt man to take over for that fight sequence. One minute, Cheyenne was the larger of the two men and the next he was smaller. It was very noticeable.