Kranitz, 52, was announced Monday as the Astros' minor league pitching coordinator, joining an organization that includes one of his closest friends, Houston manager Brad Mills.
"First and foremost, I know the people at the top there very well … and it's an organization on the rise," Kranitz said. "They're looking to continue to develop their pitchers and players, and I feel like I am the right guy to do that. It's a very good fit for me."
Kranitz's departure was not a surprise because the Orioles are expected to soon announce the hiring of Mark Connor as their pitching coach. Connor, 61, has been with Buck Showalter at each of the Orioles manager's three previous managerial stops.
Kranitz hadn't heard from anyone in Orioles management for nearly two weeks, and, when his contract expired Sunday, he felt he could no longer keep waiting.
"That's part of the process, honestly, I don't like, the waiting through October," Kranitz said. "It was tough, but I didn't hear anything through yesterday. As my contract expired, I thought it was time for me to move on."
Kranitz was the only big league pitching coach that many of the club's young hurlers knew.
"It's really tough for me," Orioles starter Brad Bergesen said. "Kranny, for me, was so influential. He was such an important part of my development over the last couple of years. I learned so much from him, not just on a professional level, but on a personal one. He knew everything I was going through this year, and he was always there to support and encourage me."
Kranitz came to the Orioles as one of the top assistants in baseball, a season removed from being named Baseball America's Major League Coach of the Year in 2006 for his work with the Florida Marlins' impressive cadre of young starters.
Life was rougher for Kranitz's inexperienced staffs in the American League East. Orioles pitchers finished last or second-to-last in AL ERA in their three seasons under Kranitz. However, the club's 4.59 ERA in 2010 was significantly lower than 2009's AL-worst mark of 5.15. In fact, the 2010 ERA was the Orioles' lowest since 2005.
"We've been able to develop a very good working relationship over the past three seasons," staff veteran Jeremy Guthrie said. "You see a lot of the positives that he brought to the pitching staff with the way a Brad Bergesen threw [in 2009] and at the end of this year and the way a Brian Matusz came up and got acquainted with the big leagues."
The Orioles had an AL-worst 5.18 ERA before Showalter took over Aug. 2. In the following two months, Orioles pitchers combined for a 3.54 ERA, including a 3.16 mark by the starters.
"The numbers speak for themselves through those last 60 games," Kranitz said. "There were a lot of friendships with those young kids, and I am going to miss them. Obviously, it is tough. I feel like some of those guys have really grown and are in a position now where they are going to take off. And I am not going to be a part of that, and, sure, that hurts."
Kranitz is just the second Orioles pitching coach to last at least three consecutive full seasons since 1995. The Orioles have had 11 pitching coaches since 1994, including two separate stints each by Ray Miller and Mike Flanagan.
Baltimore Sun reporter Jeff Zrebiec contributed to this article.