Washington Nationals manager Davey Johnson left, pulls starting pitcher Dan Haren, right, as catcher Jhonatan Solano stands center during the fourth inning of a baseball game against the Colorado Rockies at Nationals Park, Saturday, June 22, 2013, in Washington. (AP Photo/Carolyn Kaster) (Carolyn Kaster/AP)

The crowd met Davey Johnson with stinging approval the moment he emerged from the Washington Nationals’ dugout. He arrived at the mound and took the baseball from Dan Haren, and the sound at Nationals Park shifted during Haren’s lonely, vacant-eyed walk off the field. The Nationals faced a five-run deficit, Haren carried the majors’ highest ERA among starting pitchers and everyone watching had had enough. Fans booed until Haren disappeared from view, done for the afternoon, maybe for longer.

“No one wants to be booed,” Haren said later, in the quiet of the Nationals’ clubhouse. “I’d probably boo myself, too.”

The Nationals handed Haren $13 million this winter to strengthen the back of their rotation. After the Colorado Rockies pummeled him in a 7-1 loss Saturday afternoon, they may not be able to justify giving him another start. Haren retired one batter before he yielded a home run, recorded just 10 outs total and, before the game was half-expired, obliterated the momentum the Nationals gathered during a three-game winning streak.

Haren allowed six earned runs in 3 1 / 3 innings, the worst start of a nightmare season. The Rockies ripped seven hits, starting with DJ LeMahieu’s home run in the first and ending with pitcher Jhoulys Chacin’s RBI single in the fourth. Haren mixed in two wild pitches, one of which pushed home a run. His ERA rose to 6.15.

Haren has vacillated between adequate and awful all year, but his recent penchant toward the latter reached a critical juncture Saturday.

“I don’t want to speculate on what I’m thinking about right here,” Johnson said. “But I do have some concern.”

“I’d be lying if I said I haven’t thought about it,” Haren said. “It’s a performance-based business. I’m not getting the job done.”

Johnson will attend Haren’s side session Monday, a day off for the team, before determining whether Haren will make his next start. Johnson wondered if a physical issue had led to Haren’s recent series of meltdowns.

“There might be something bothering him I don’t know about,” Johnson said. “If it’s something physical, sometimes you miss a start, that kind of thing.”

Haren, 32, raised red flags this winter after hip and back issues surfaced last season. He insisted his disastrous seasons owe to simple performance, not health.

“There’s aches and pains,” Haren said. “Nothing I haven’t pitched through in the past. Physically, I’m okay. I’ve been better. I’ve been worse. It’s still no excuse for what’s going on.”

What’s going on is this: One of the most accomplished right-handers of the last decade has devolved into one of the most hapless starters in baseball. From 2003 through 2012, only six pitchers compiled more wins above replacement. No pitcher has thrown more inviting pitches this season. Opposing hitters have clobbered 19 home runs and compiled an .879 on-base-plus-slugging percentage against him, both the highest totals in the National League.

His fastball, splitter and cutter all hover at roughly the same speed, between 84 and 91 mph. For years, the combination confused and overwhelmed opponents. This year, because of diminished velocity, less movement and poor location, they have resembled batting practice.

“After the last several starts, it’s hard to remain confident in between,” said Haren, who has allowed 20 earned runs in his last 18 1/3 innings. “I’ve never gone through something this tough in my career. It’s definitely a battle to stay confident. There’s self-doubt that creeps in there for everybody whenever they’re not doing well. Obviously, I’ve been struggling for a while now.”

Johnson has noticed Haren trying to add extra velocity to his fastball and cutter, which causes him to open his front shoulder too soon. The glitch has robbed his cutter of the darting movement that makes it effective. When he leaves the cutter up, which is often, it has been clobbered.

“We’re all looking, seeing if we can see anything,” first baseman Adam LaRoche said. “Is he tipping a pitch or falling into patterns? I don’t see any of that. Right now, I think it’s just bad luck. He cannot miss up in the zone, or it’s getting smoked.”

Saturday afternoon, the Nationals’ lineup floundered yet again, this time with Jayson Werth scratched an hour before the game because of flu-like symptoms, according to Johnson. It may not have mattered who pitched as Chacin steamrolled the Nationals’ offense, which avoided its ninth shutout of the year only when Ryan Zimmerman mashed a cosmetic homer in the ninth.

Since May 14, the Nationals are 0-8 when Haren starts and 16-12 when he does not. Removing him from the rotation would be a financial blow, since the Nationals still owe him roughly $6.5 million. The alternative may be less palatable. Because they have Monday off, the Nationals could bypass Haren’s spot in the rotation and not replace him until June 30.

The Nationals might not have to look far for a suitable replacement. Saturday, Ross Ohlendorf relieved Haren and used his old-school windup and a fastball that reached 96 mph to quiet the Rockies for 4 2 / 3 innings. He held them to four hits, including a solo home run by Nolan Arenado, the only run he allowed.

The question of who will start for the Nationals in five games surfaced after a start that typified Haren’s season. He showed brief glimpses of his old self, retiring every batter he faced in the second and third innings, striking out five Rockies overall. As ragged as his last four starts have been, he shut down the Baltimore Orioles for 7 1 / 3 innings May 30.

“That’s what’s been so perplexing,” Haren said. “I’ll have spurts where it almost seems easy. And then there’s spurts where I can’t get anybody out. I wish I had more answers. It’s just still searching for ways to get better.”

The answers never came Saturday. He allowed three runs in the first and then, just as it seemed he had settled, the Rockies struck for another three runs off him in the fourth. Johnson climbed the dugout steps and lifted his right arm toward the bullpen, calling for another pitcher. He took the ball from Haren, and whether or not he will give it back to him in five games had become an open question.