Starting pitcher Mark Buehrle opted to join the Miami Marlins and his former manager, Ozzie Guillen, rather than the Washington Nationals. The Nationals had made Buehrle their No. 1 target in the offseason. (Jim Prisching/AP)

The Washington Nationals pinned their highest winter hopes on signing Mark Buehrle, the free agent pitcher they believed would turn their young, deep rotation into one of the league’s best.

In October, they envisioned slotting him between Stephen Strasburg and Jordan Zimmermann, a savvy, experienced lefty in the middle of two young, electric right-handers. In November, they flew to his home in St. Louis and explained both how he would help them win and how happy his family would be in Washington.

On Wednesday, they met with his representatives and presented their best offer. And they felt good about it.

Their plans, their diligence, their offer, all of it was dashed Wednesday afternoon, consumed by the growing powerhouse known as the Miami Marlins. The Nationals missed out on the Plan A of their offseason when Buehrle agreed to a four-year, $58 million contract with the Marlins, choosing more money and a reunion with Ozzie Guillen, his manager with the Chicago White Sox, over the Nationals.

The Nationals’ best offer, made Wednesday morning, fell short of what the Marlins offered in duration and salary per season. The Nationals and Buehrle exchanged constructive dialogue, and he had significant interest in Washington. But the Nationals’ efforts and their desire to land Buehrle turned into frustration.

With Buehrle going to a divisional rival that had previously added closer Heath Bell and shortstop Jose Reyes, the Nationals will move on.

The Nationals will target right-hander Roy Oswalt, multiple people close to the Nationals said. Oswalt also fits the profile General Manager Mike Rizzo desires, a veteran starter capable of adding experience to their rotation and lessening the burden on Strasburg as he pitches his first full season since Tommy John surgery.

Oswalt, 34, went 9-10 with a 3.69 ERA, 93 strikeouts and 33 walks for the Philadelphia Phillies last season.

Back issues limited Oswalt to 139 innings over 23 starts. Over the previous nine years, Oswalt threw 208 innings per season. Oswalt seeks a three-year deal, reported.

The Nationals also have kicked the tires on Oakland A’s left-hander Gio Gonzalez, but the asking price for Gonzalez, a 26-year-old with four years remaining before he hits free agency, is likely too exorbitant for the Nationals.

And they have shown interest in Japanese superstar Yu Darvish, who is expected to come available later this winter via the posting system. One final target is Tsuyoshi Wada, a left-handed Japanese free agent.

If the Nationals started the season with their current rotation, they would still have a solid starting five of Strasburg, Zimmermann, John Lannan, Chien-Ming Wang and Ross Detwiler, with rookies Brad Peacock and Tommy Milone also competing.

“We feel that we have good depth with starting pitching with what we have in-house,” Rizzo said.

Said Manager Davey Johnson: “You know, I really like my staff. I like it as it is right now. Any time you can improve, go for it. I haven’t been pushing in that direction.”

But missing out on Buehrle also affects the Nationals’ pursuit of a center fielder. With an additional starter, the Nationals could have used their substantial starting pitching depth in a trade for a center fielder. Had the Nationals acquired Buehrle, it would have given “us more options, definitely,” Rizzo said.

(If the Nationals are able to trade one of their starters, it is more likely they deal Detwiler than Lannan, if only because Detwiler has yet to become eligible for arbitration and is under team control for five more seasons.)

The Nationals badly wanted Buehrle. In the end, their offer just fell short.

“We’ve put our best foot forward,” Rizzo said before the deal. “We made what we feel is a legitimate, fair, market-value offer. We’re hoping that he likes our opportunity and comes aboard.”

“I feel good about how we presented it,” Rizzo said before the news broke. “I feel good about the fit and the opportunity. We had good dialogue with Mark and his people. We feel good about ourselves.”