WASHINGTON - The Nationals believe Trea Turner can help them catch the NL East-leading Mets, even if it's not quite clear how just yet.

The 22-year-old shortstop, one of baseball's top prospects, made his major league debut Friday, showcasing his speed and experiencing his first replay review in Washington's 10-3 loss to the Milwaukee Brewers.

"I thought I was going to be more nervous," said Turner, who went 0 for 2 after entering the game as part of a double-switch in the seventh inning. "But at the same time, I felt like I was doing some uncharacteristic things. I felt like I couldn't control my body sometimes."

Bryce Harper hit his 31st home run and Michael Taylor also homered for the Nationals, who fell five games behind the NL East-leading New York Mets.

Gio Gonzalez (9-6) allowed five runs — four earned — over five innings, and the Brewers added a five-run seventh. Washington lost the opener of a nine-game homestand following a 3-7 West Coast trip that ended with a night game in Denver on Thursday.

"We get some more sleep, that's basically it," Gonzalez said when asked how his team can bounce back. "We get some more sleep and try to come back and get ready for them tomorrow."

Turner was called up from Triple-A Syracuse to replace Tyler Moore, who was placed on the 15-day disabled list with a sprained left ankle. He was batting .322 with eight home runs and 54 RBIs and 29 stolen bases in 116 games between Double-A and Triple-A.

"We wanted to get another right-handed bat that could help us," Nationals GM Mike Rizzo said. "We thought Trea was going to be a September call-up anyways, just, we felt, maybe this is a time to inject a little more speed, youth and athleticism into the ballclub."

He showed that speed in the seventh, nearly beating out a grounder to short and forcing a replay review of about 2 minutes.

"At first when he called me out, I'm like, I'm out," Turner said. "And then everyone's yelling at me to stay on the base. So it was a little bit different."

Turner could see time at second base and is likely to be eased into action, Rizzo said. He was acquired from San Diego in mid-June to complete a three-team deal that brought rookie right-hander Joe Ross to the Nationals and sent outfielder Steven Souza Jr. to Tampa Bay.

"He takes a while to warm up to each level that he's played at," Rizzo said. "So we're not expecting him to be the saviour of the offence or the saviour of the ballclub. We just want him to do what he does best."

Washington already has depth at its middle infield spots, though offensive production has lagged.

Nationals shortstop Ian Desmond is hitting .227 with 15 home runs and 45 RBIs this season, but is .274 with eight of those homers since the All-Star break. Second baseman Anthony Rendon is batting .247 over 40 games after dealing with separate knee and quadriceps injuries early in the season and utility man Danny Espinosa is .248 with 12 homers and 33 RBIs.

Desmond said he welcomed the move.

"This is about winning right now," he said. "It's not about personal agendas here. This is about the Nationals and getting Ws and that's got to be our focus."

PINCH HIT PITCHER

Nationals right-hander Max Scherzer pinch hit for Gonzalez in the top of the fifth inning, smacking a liner to first base.

TRAINER'S ROOM

Nationals: 3B Yunel Escobar left the game in the first inning after suffering an apparent injury trying to catch a foul ball. ... RHP Aaron Barrett (right elbow sprain) was transferred to the 60-day disabled list before Friday's game. He last pitched on Aug. 5. ... CF Denard Span (back tightness) was expected to play seven innings with Double-A Harrisburg Friday in his fourth rehab outing

UP NEXT

Brewers RHP Taylor Jungmann (7-4, 2.23 ERA), who has made eight consecutive starts without allowing a home run, will face Nationals RHP Joe Ross (3-5, 3.86), who went eight innings in his previous start against Milwaukee.