Rockies center fielder Dexter Fowler scores the tying run on a wild pitch as Nationals relief pitcher Mike Gonzalez tries to make the diving tag in the eighth inning. (Toni L. Sandys/The Washington Post)

Baseball, once again, has regained relevancy in Washington. The Nationals continue their transformation into a team that, at least to this point of the season, can excite, contend and inspire dreams of fall baseball. Attendance and interest are up, and the team has spent the better portion of the season’s first three months in first place in its division.

Even with a late-game collapse in a 4-3 loss to the Colorado Rockies on Sunday, the final game of the first half of their season of rebirth, the Nationals came close to setting a new high. They enter the all-star break with a .590 winning percentage, just a hair away from matching their best mark (.591) since baseball returned to the District in 2005.

Two wild pitches essentially kept them from taking the game and the series from the visiting Rockies. While players admitted it was frustrating to lose, what happened on Sunday isn’t any cause for alarm. They will enter the all-star break with the National League’s best record (49-34). They hold a four-game lead in the National League East. They have four all-stars, the most they’ve had since baseball returned. Things are different here.

“We can’t let tonight affect what we did the last three months,” reliever Sean Burnett said.

On a starting rotation that features two all-stars, right-hander Jordan Zimmermann continued his consistent, inning-churning ways. Shortstop Ian Desmond, an all-star that had to pull out of the game because of injury, maintained his torrid hitting pace in his breakout season. But Washington’s bullpen, a point of strength this season, faltered for the first time in 11 days.

“They’ve been having our backs in some tight situations all year,” Zimmermann said. “This one got away. We gotta move past it and focus on the second half.”

Zimmermann’s seven-inning gem began unraveling when the bullpen took over on an unbearably humid afternoon. Players escaped the 95-degree heat and sticky air by retreating to the air-conditioned clubhouse and adjacent tunnel during the game. Zimmermann withstood it well, cruising through the Rockies’ lineup. Despite that, Manager Davey Johnson watched Zimmermann hitter by hitter in the seventh inning and wasn’t going to let him continue in the heat.

Johnson handed the ball and a 3-1 lead to Burnett. Normally a two-run lead secured under the starter has meant little trouble for the bullpen and in particular Burnett, who entered with a 1.42 ERA.

But pinch hitter Eric Young Jr. hit Burnett’s fourth pitch, a sinker, out to left field for a solo home run in the eighth inning. He faced two more batters, and gave up singles to each of them. Michael Gonzalez replaced Burnett with no outs.

“Just one of those things it didn’t go my way today,” Burnett said. “Unfortunately you can’t get the ball and go out there tomorrow.”

With runners on first and third and with a 2-2 count on Carlos Gonzalez, Michael Gonzalez tossed a low slider away in the dirt, looking for the strikeout. The ball was too far outside and bounced, and catcher Jhonatan Solano couldn’t stop it. Dexter Fowler safely scored from third.

So now, the lead was lost, but not the game. Johnson turned to another bullpen stalwart, Tyler Clippard, for the ninth inning. The right-hander hadn’t allowed a run in 20 appearances, so he seemed like a sure bet in a 3-3 game.

He gave up a leadoff double to Jordan Pacheco, who advanced to third on a sacrifice bunt. Facing pinch hitter Jason Giambi with a 1-1 count, Clippard turned to his change-up. Solano set up to receive the pitch away; instead it sailed inside and bounced just in front of Solano’s glove and scuttled away to the backstop. Pacheco darted home and scored without a play. “I can’t remember the last time I threw a wild pitch,” Clippard said.

Desmond led off the ninth with a single and Roger Bernadina drew a walk against closer Rafael Betancourt. Down to their last out and with pinch hitter Jesus Flores at the plate, Johnson called for Desmond and Bernadina to steal. They did, putting the winning run in scoring position. Flores struck out.

While starters Stephen Strasburg and Gio Gonzalez were selected as all-stars for their performances so far this season, Zimmermann continued to be the most quietly consistent starter in the rotation. He has now pitched at least six innings in all 17 starts of this season. He leads the team in innings pitched (1101 / 3 innings) and ERA among starters (2.61). Zimmermann allowed only five batters to reach base on Sunday, three of them in the second inning.

Zimmermann, whose 5-6 record is a poor reflection of his performance because of low run support, received enough from the team’s other consistent performer: Desmond. The shortstop’s career season continued and his red-hot bat showed no letup.

He crushed a two-run home run to center field off starter Jeremy Guthrie to give the Nationals a 2-1 lead in the fourth inning. Even with a nagging sore oblique that caused him to pull out of Tuesday’s All-Star Game, Desmond has shown few ill effects from it. He leads all shortstops in the major leagues in home runs (17), RBI (51) and slugging percentage (.515). In the past 11 games, Desmond has hit six home runs and driven in 13 runs.

The Nationals added a third run in the seventh inning on an RBI single by Steve Lombardozzi. But it wasn’t enough as they walked off the field at Nationals Park with another deflating loss to Colorado, their fourth in seven games against one of the worst teams in the major leagues.

Injuries have ravaged this Nationals team, sending 15 players to the disabled list, yet they are atop their division. They return to the field on Friday, facing a four-game series in Miami, in the thick of a pennant race — not trying to climb out of the bottom of the standings like in years past.

“Maybe it’s a blessing in disguise,” Desmond said. “It’ll get us to come back after the break and still be hungry. Kind of good to go out on a little bit of a sour note.”