Dan Haren allowed two runs in five innings in his return from the disabled list, but the Nationals lost, 3-2, to Philadelphia on Monday night. (Hunter Martin/GETTY IMAGES)

Dan Haren, above all, wanted Monday night to be different. He held his splitter with a wider grip. He peppered the outside third of the plate. He wore his pants pulled high to reveal red socks. Nothing had worked earlier this season, and so in his first start back from the disabled list, Haren changed, right down to his uniform.

“Usually, I don’t really like to, because my calves are pretty embarrassing,” the Washington Nationals right-hander said. “I figured I’d give it a shot. I’ve tried everything else.”

The tweaks led to an indeterminate conclusion in the Nationals’ 3-2 loss to the Philadelphia Phillies at Citizens Bank Park. Haren flirted with disaster in a two-run first inning, then dodged trouble long enough to finish his five-inning start with four scoreless frames. He lasted 95 pitches and took his 10th loss, but his manager found enough to be encouraged.

“He threw the ball very well,” Davey Johnson said. “I was pleased with his command. I was pleased with his stuff. He threw a lot of pitches, and that’s the only reason I didn’t let him go back out there, but he threw the ball really good. I’m glad to have him back.”

Haren’s return was overshadowed by former National John Lannan, whose sinker silenced the Nationals’ suddenly streaking lineup for eight scoreless innings and halted their winning streak at four, even after the Nationals’ frenzied ninth-inning rally.

Haren had been one of the majors’ least-supported pitchers when he went on the disabled list 15 days ago, and that much stayed the same. Lannan nearly handed the Nationals their 10th shutout of the season, splashing cold water over an offense that had scored 56 runs over its previous eight games.

“I feel like I just beat my head against the door for three hours,” said shortstop Ian Desmond, who went 0 for 4 with three strikeouts.

Once Lannan exited, the Nationals bullied closer Jonathan Papelbon, whom they had twice come back on during their June series in Philadelphia. Bryce Harper led off the ninth inning with a single. Ryan Zimmerman smashed a double off the right-center field wall. After walking to the plate drenched in customary boos, Jayson Werth smashed a deep drive to center field.

“He hit the heck out of it,” Johnson said. “I was hoping.”

But center fielder Ben Revere tracked the ball down on the warning track, just in front of the 398-foot sign. Harper dashed home. As Werth walked back into the dugout, he slammed his helmet off the ground. The game-tying homer had turned into a sacrifice fly. Adam LaRoche provided another sac fly, but the Nationals’ rally died when Chad Tracy followed with another flyout.

Whatever the result Monday night, the Nationals’ most pressing issue remained whether Haren can solidify the uncertain back of their rotation. With Ross Detwiler on the disabled list and a rookie from Class AA, Taylor Jordan, holding one rotation spot, the Nationals’ $13 million right-hander has become a hinge. Can the Nationals rely on him after a cortisone shot and rest? Or is he the same starter who compiled a league-high 6.15 ERA before he landed on the disabled list?

In his first effort, Haren allowed 10 base runners — seven hits and three walks — but also struck out seven. His cutter missed bats, and he allowed no home runs. But he also walked in a run, his third career bases-loaded walk in 302 starts.

“It felt pretty much the same,” Haren said. Later, though, he added: “Overall, I feel good. Excited to take the ball in five days. My stuff feels good and where it needs to be.”

General Manager Mike Rizzo said Monday he did not anticipate making any “splashy” trades before the deadline, but “it could always change.” Still, two major league executives said they expect the Nationals to seek a starting pitcher on the trade market. One of them said the Nationals seemed to be in a “holding pattern” as they waited for Haren to come off the disabled list so they could evaluate him.

If so, their evaluation Monday night could lead to few definitive conclusions. Haren’s recovery provided encouragement, but his first inning created doubt.

Revere flared a single to right, and Jimmy Rollins lashed another to left. Three pitches into Haren’s return start, the Phillies had runners on first and second base. Revere and Rollins promptly executed a double steal, and two runners stood in scoring position with no outs.

Haren struck out Chase Utley. With one out, Domonic Brown’s line drive drilled Haren in the shin and trickled toward first base for an RBI single. Haren limped back to the mound. The first inning had turned into tragicomedy.

“Before I knew it,” Haren said, “I was in trouble.”

Michael Young walked to load the bases. Haren came back with another strikeout, then moved one pitch away from escaping with a 2-2 count on Darin Ruf. But Haren missed twice off the outside edge of the plate, and his rare bases-loaded walk pushed across the Phillies’ second run.

Just as Haren neared another abyss, he gathered himself. He danced around a leadoff walk and a single in the third inning. He cruised through a 1-2-3 fourth. He fell into a rhythm with catcher Wilson Ramos, and Phillies kept lunging at cutters outside. In the fifth, consecutive two-out singles gave the Phillies a rally, but Haren threw a cutter past Ruf with his 95th and final pitch.

“We expect him to win games, keep us in games, pound the strike zone, utilize his command of his three pitches and get guys out,” Rizzo said. “That’s what he expects of himself, and that’s what we expect from him.”

After Monday night, it wasn’t clear what the Nationals could expect from Haren. He pitched only well enough for another chance to prove he can still be a different pitcher.