Dodgers’ deal with Hisashi Iwakuma falls apart and pitcher re-signs with Mariners

The Dodgers settled on their coaching staff Thursday, but the more important composition of their pitching rotation became even more of a mystery as their agreement with free-agent right-hander Hisashi Iwakuma unraveled because of medical concerns.

Iwakuma is returning to the Seattle Mariners on a one-year contract, as the Dodgers retracted their three-year offer in the wake of the physical examination he underwent last week.

The loss of Iwakuma marks the latest disappointment for the Dodgers in what has been a potentially devastating winter, which started with them losing Zack Greinke to the division rival Arizona Diamondbacks. The Dodgers were set to acquire Aroldis Chapman last week from the Cincinnati Reds, only for that trade to be placed on hold when the All-Star closer became the subject of a domestic-violence investigation by the commissioner’s office.

The Dodgers reached an agreement last week with the 34-year-old Iwakuma on a $45-million contract, which was pending a physical examination. The results of that examination were problematic, according to Japanese news reports.

The team continued to negotiate with Iwakuma into this week, according to a person familiar with the situation who spoke under the condition of anonymity because of the sensitive nature of the talks. The Dodgers were believed to be looking to restructure the contract, much like the Boston Red Sox did with Mike Napoli before the 2013 season. Napoli agreed to a three-year, $39-million deal, but his physical examination revealed problems with his hip. Napoli settled for a one-year contract with a base salary of $5 million.

The Dodgers were looking for Iwakuma to be the only right-handed starter in a rotation that consists of Clayton Kershaw, Brett Anderson, Alex Wood and Hyun-Jin Ryu. But a new deal was never finalized.

Iwakuma instead decided to re-sign with the Mariners, for whom he pitched in each of his four previous major league seasons. Iwakuma’s new contract with the Mariners includes vesting options for 2017 and 2018.

By losing Iwakuma, the Dodgers have regained their first-round pick in the draft next year. They would have forfeited the selection if they had signed him, since he had previously rejected a qualifying offer from the Mariners worth $15.8 million.

Uncertainty over Iwakuma’s status probably factored into the Wednesday acquisition of three prospects from the Chicago White Sox who could be part of a package to trade for a young frontline starter such as Jose Fernandez, Sonny Gray or Carlos Carrasco.

The Dodgers will also be paying a refundable $20-million posting fee to negotiate with another Japanese right-hander, Kenta Maeda, according to a person familiar with the team’s thinking. Maeda won the Japanese league’s equivalent of the Cy Young Award this year.

Other free-agent starting pitchers still available include Mike Leake, Yovani Gallardo and Scott Kazmir.

If there’s any consolation for the Dodgers, it’s that Manager Dave Roberts’ coaching staff is in place, which will allow the front office to focus on the roster.

Gabe Kapler, who was a finalist for the managerial position, was expected to be part of it. However, Kapler, a longtime favorite of President of Baseball Operations Andrew Friedman, will remain the farm director.

Holdovers from Don Mattingly’s staff will include pitching coach Rick Honeycutt and catching instructor Steve Yeager. Bullpen catchers Rob Flippo and Steve Cilladi will also return.

The rest of the staff will be newcomers.

Bob Geren, former manager of the Oakland Athletics, will be Roberts’ bench coach. Geren was most recently the bench coach of the New York Mets.

Turner Ward will be the hitting coach, with Tim Hyers serving as assistant hitting coach. Ward used to be the hitting coach of the Arizona Diamondbacks.

With Kapler remaining in the front office, George Lombard will coach first base and Chris Woodward third.

Josh Bard, a former teammate of Roberts on the San Diego Padres, will be the bullpen coach.

Former major league infielder Juan Castro will be in the newly created position of quality assurance coach. The only member of the staff who speaks Spanish, Castro will help Woodward with the infield defense. He will not be in uniform during games.

Twitter: @dylanohernandez