Mike Maddux will reportedly join the Cardinals’ coaching staff. (AP Photo/Lynne Sladky)

When they decided not to renew Dusty Baker’s contract, the Washington Nationals guaranteed themselves an offseason of transition. But transition evolved into transformation Thursday, when pitching coach Mike Maddux agreed to fill the same position for the St. Louis Cardinals, leaving another vast hole in a coaching staff that had seemed to be well-tailored to the clubhouse it served.

The Nationals confirmed they had heard Maddux would be leaving. He was free to talk to other teams for the last week, as his two-year contract with the Nationals had expired. That contract, which Maddux signed before the 2016 season, represented a surprising commitment from the Nationals’ front office, which generally does not commit to coaches for more than one year.

At the time, the Nationals hired Maddux independently of their manager, an indication of his stature within the game and their commitment to the pitching staff, around which General Manager Mike Rizzo has built his four division winners. But now, that largely veteran pitching staff will fall into the hands of a third pitching coach in four seasons.

In the days since Baker’s departure, more than one member of the organization expressed the hope that keeping Maddux would be a priority. He knew the pitching staff inside and out. He understood the personalities, worked well with the big names like Max Scherzer and Stephen Strasburg, and maintained a consistent commitment to detail. But Maddux’s stature in the game virtually ensured others would call if the Nationals hesitated, and Bob Nightengale of USA Today reported that five teams pursued him in the last week. He chose the Cardinals, leaving the Nationals to a shrinking pool of potential pitching coaches — and to decide whether to wait to hire a manager before choosing one.

Former Rays pitching coach Jim Hickey and former Giants pitching coach Dave Righetti are among those available. Former Cubs pitching coach Chris Bosio is an intriguing name, particularly as the Nationals will be interviewing Cubs bench coach Dave Martinez for the manager position, and he could therefore bring a familiar face along with him. The Nationals are not the only team hunting a pitching coach, as the Mets, Phillies, Giants, Cubs and others will all do the same in the coming weeks.

Whoever the Nationals choose, that man will be entrusted with one of the best pitching staffs in baseball over the last five seasons — a staff Maddux guided to a 3.70 ERA during his two-season tenure, which trailed only the Cubs and Dodgers among National League teams. Maddux’s staffs averaged 9.08 strikeouts per nine innings and a 3.05 strikeout-to-walk ratio in that span, which trailed only the Dodgers in the National League.

Most of the Nationals’ rotation will be back next season: Scherzer, Strasburg, Gio Gonzalez and Tanner Roark are all under contract. Youngster Erick Fedde, who Maddux helped hone a big-league-ready curveball this season, should push for a spot as the fifth starter. Sean Doolittle and Ryan Madson will both be back to provide keystones in the bullpen, though names could change around them.

Whoever comprises the staff will be working with a new pitching coach this season, as another experienced Nationals coach got away, leaving Rizzo and the front office to fill more holes on an experienced coaching staff now disintegrating.

More on the Nationals:

Girardi is out as Yankees manager, and the Nationals just happen to have an opening

What will happen to the rest of the Nationals’ coaching staff?

Rendon and Taylor are named Gold Glove finalists

Robles homers to cap strong start to first week in Arizona Fall League

There’s a chance Daniel Murphy won’t be ready for Opening Day