MILWAUKEE -- The Pirates welcomed two new faces into their clubhouse on Sunday morning and debuted both in the eighth inning of their 4-2 loss to the Brewers at Miller Park.
Newly acquired reliever Felipe Rivero made his first appearance for his new team, throwing a scoreless frame while striking out two and giving up a hit and a walk. Infielder Max Moroff, recalled from Triple-A Indianapolis, struck out as a pinch-hitter in his Major League debut.
Rivero, half of the Pirates' return from the Nationals for closer Mark Melancon, flew into Milwaukee early Sunday and reported to the visitor's clubhouse at Miller Park.
Typically expected to pitch with a lead in the seventh inning in front of Neftalí Feliz and new closer Tony Watson, Rivero trotted to the mound with the Pirates down two in the eighth.
Rivero struck out Scooter Gennett with an 84-mph slider, before giving up a single to Martín Maldonado and striking out Kirk Nieuwenhuis with another slider -- an unusual sequence for a self-described fastball-changeup reliever.
Rivero walked Keon Broxton but got pinch-hitter Jonathan Lucroy to pop out to shallow right field to end a 30-pitch inning.
"It's power, and there's some spin to it. He might have been a little over-amped," manager Clint Hurdle said. "Pitch efficiency was a little rusty. ... He got the first one under his belt."
Rivero wasn't expecting to be traded. He was taking a shower, getting ready for Saturday's game, when he heard Nats manager Dusty Baker wanted to talk to him.
"I'm like, 'I'm in trouble,'" Rivero said, smiling. "Then they talked to me and I was also surprised then. ... It's cool, man. New stage in my life, new chapter."

Rivero, who will wear No. 73, posted a picture he took of PNC Park last year on Twitter late Saturday night. When he heard he'd been traded to Pittsburgh, he scanned his phone, saying, "I think I've got something."
Rivero is under club control for five years after this season. Some evaluators have pegged him as a future closer.
"I've just got to keep working," Rivero said, "and the day will come."
Moroff, Pittsburgh's No. 26 prospect according to MLBPipeline.com, joined the club in place of left-hander Steven Brault, who was optioned to Indianapolis after starting Friday's game in Milwaukee.
"Very overwhelming. Didn't sleep at all last night," said Moroff, who will wear No. 38. "Walking in here, it's pretty sweet seeing all the guys from Spring Training again. Looking forward to it."
The 23-year-old, switch-hitting utility infielder was hitting .229/.360/.368 with seven homers and 41 RBIs through 101 games in Triple-A.
Hurdle noted that the addition of Moroff, a versatile defender, will free up the Pirates to more frequently and aggressively deploy fellow infield prospect Adam Frazier, who has performed well in his first stint in the Majors.
Why not recall first-base prospect Josh Bell? GM Neal Huntington said on 93.7 The Fan the Pirates didn't want to disrupt Bell's work with another brief stint in the Majors.
Moroff and Rivero were the 45th and 46th players to appear for the Pirates this season, nearing the club record of 52 established in 2011. Moroff became the 10th Pirates player to make his Major League debut this season, striking out against lefty reliever Will Smith to lead off the eighth.
Moroff's stay will likely be brief, as the Pirates have to rebalance their roster and activate right-hander Ryan Vogelsong to start Thursday's game in Atlanta. In the meantime, Moroff will follow the advice provided by his fellow rookies.
"Soak it all in. Look around. Keep quiet," Moroff said. "Just have fun."