In most rules, once a pitcher is removed as pitcher, he may not return to the position of pitchers. Only certain leagues have by-laws that would allow this for a starting pitcher, let alone a reliever.
The pitcher's mound is circular.
A pitcher has a high mound because he can get some velocity.
There is a pitcher's circle but no actual mound of dirt. There is a pitcher's circle but no actual mound of dirt.
What is the height of the pitcher's mound in college baseball
The sport of baseball has a pitcher's mound.
The Pitcher stands on the mound.
The pitcher is on the mound so he can't charge it. The batter charges it from the plate.
It is 40 feet from the pitcher's mound to home plate.
No. Once a player is removed from the game, they cannot re-enter that game.
The diameter of an MLB pitcher's mound is 18 feet.
The diameter of the pitcher's mound on an MLB baseball field is 18 feet.
Answer: Yes. It happened frequently in high school baseball in the 1950's, '60's, and '70's. It has happened in the major leagues a few times.