"The Sheridan Story"
Wanting to teach Mark a lesson in tolerance and acceptance, Lucas hires an injured and bitter confederate soldier to work on his ranch, but when a Union army comes to stay the night as well, trouble erupts.
From "The Rifleman Episode Guide"
Of the many historical figures from the Civil War to be depicted on television, Phil Sheridan hasn't had many portrayals in TV shows. (President Lincoln and General Grant probably lead the pack.)
The difference in Sheridan's appearance between various programs could be attributed to several factors. One could be the passing of time - his portrayal in 'The Rifleman' was at least fifteen years after the Civil War ended, making him older than the fleeting appearance he had in another Chuck Connors Western, 'Branded'.
Another factor, specific to this episode of 'The Rifleman', is that the hardship of life on the trail as he and his men traveled the Southwest may have taken its toll on him.