All of the coaches, including Young, were under contract for 2013.
Young joined manager Kirk Gibson's coaching staff in 2011, and in addition to coaching first base, he was involved in working on baserunning and outfield play.
The D-backs struggled on the bases in 2012. They were caught stealing 52 times -- second-most in the Majors -- and improving the baserunning was something that Gibson mentioned at the end of the season.
"It is an area that we need to improve upon and it is an area that we will try to improve upon," Gibson said. "Again, it's not like one reason or one thing, and again, I really want to be cautious about blaming Eric Young for our shortcomings because as I said earlier, it's all on me."
Gibson notified Young of his decision by phone Wednesday and the team expects to start conducting interviews for a replacement late this week or early next week.
D-backs general manager Kevin Towers said both internal and external candidates would get interviews. While both Towers and Gibson declined to get into specific names, Triple-A manager Brett Butler and Double-A manager Turner Ward would seem to be strong internal candidates.
"I wouldn't say there's any frontrunner right now, but we've been kind of compiling a list knowing this was probably a decision we were going to be making with E.Y.," Towers said.
As for the new coaching position, the D-backs are following a trend set by teams like the Cardinals and Padres in adding a seventh coach to the staff whose main responsibility is to assist the hitting coach.
"It's a very demanding job," Towers said of the hitting coach. "Probably the most demanding job."
Baylor has been part of the coaching staff for the last two seasons, and both Gibson and Towers said Baylor was open to the idea of adding a coach to work with him.
Whoever fills the role as the assistant hitting coach will travel with the team and be able to work on the field during batting practice. However, he will not be able to be in uniform in the dugout during games as teams are limited to just six coaches.
Communication is key in a situation with two hitting coaches, which is why Baylor will be a part of the process of selecting the new coach.
"When we get down in the process, getting close on some guys I probably will have 'Groove' talk to him and get him to sign off and get his blessing for sure," Gibson said. "'Groove' is definitely the hitting coach, he'll remain that. Exactly how it's going to break down and who has what responsibilities is yet to be determined."