The Washington Nationals are mired in a season-high four- game losing streak and will begin a six-game homestand tonight with the first of three games versus the Arizona Diamondbacks.

Washington was swept in three games at Los Angeles over the weekend and recently dropped a 2-0 decision Sunday from Chavez Ravine. Nationals young phenom Bryce Harper, who will make his home debut Tuesday, had one of his team's four hits and starting pitcher Gio Gonzalez suffered the tough-luck loss for allowing both LA runs in the sixth inning.

Gonzalez lasted six frames, struck out seven and walked five batters.

"I kind of put it in a way where I was beating myself there. I was trying to be too perfect -- to throw pitches too perfectly. It kind of got away from me," Gonzalez said of the sixth inning.

Another Nationals prospect, Tyler Moore, was recalled prior to the game and was in the starting lineup. Moore led off the fifth inning by dropping a single into the gap in right field for his first major-league hit.

The NL East-leading Nationals have lost four in a row since dropping six straight from August 23-28, 2011. They are one-half game ahead of Atlanta in the division. Outfielder Jayson Werth was a late scratch because of a migraine and should be back in the lineup Tuesday. Washington will also host Philadelphia on the homestand and is 8-2 as the host this season.

Jordan Zimmermann is coming off his first win of the season and will get the nod for the Nationals this evening. Zimmermann has yielded one earned run in each of his four starts this season and lasted six innings in Wednesday's 7-3 victory at San Diego.

Zimmermann struck out a season-high six batters and did not issue a walk for a second straight start. The righty will make his third home start of the season and third against the Diamondbacks. He is 1-1 with a 2.03 ERA against them.

Arizona is in the midst of playing 17 games against NL East foes and took three of four games in Miami to kick off a 10-game road trip. In Monday's 9-5 victory over the Marlins, Justin Upton and Cody Ranson both hit two-run homers and Willie Bloomquist drove in a pair of runs.

A.J. Pollock had two hits and an RBI for the Diamondbacks, who are 6-4 away from the desert and Patrick Corbin earned the win in his major league debut. The lefty was reached for three runs and eight hits in 5 2/3 innings, and was bailed out by a potent offensive attack. He fanned six batters and walked three.

"I felt a little bit like I was trying to make a perfect pitch, throwing a little bit more balls than I wanted but I feel like I came back and battled back today," said Corbin, who was called up from Double-A Mobile.

The D'Backs are scheduled to visit the Mets for three games after this series in the nation's capital.

Arizona starter Trevor Cahill will try to stop a personal two-game slide when he makes his fifth start of the season Tuesday. He has been hammered for 11 runs -- eight earned -- in his last two appearances and took the loss in Wednesday's 7-2 setback versus Philadelphia. Cahill lasted 5 1/3 innings and gave up four runs and six hits, falling to 1-2 with a 3.70 ERA in four starts.

Cahill, a right-hander, is 1-0 in two road starts this season and will face Washington for the first time tonight.

The Diamondbacks and Nationals are meeting for the first time this season, and Arizona won five of the eight encounters a year ago. The D'Backs are unbeaten in the previous three matchups.