PHOENIX -- Two All-Stars are set to head to the mound Sunday when the Washington Nationals and Arizona Diamondbacks conclude their three-game series.

Stephen Strasburg (10-3, 3.21 ERA) is scheduled to start for the Nationals versus the Diamondbacks' Robbie Ray (9-4, 2.97).

Ray was named to his first All-Star team, though he did not pitch. He has allowed only three runs over 12 innings in his last two starts. In his last four home starts, he is 3-1 with a 2.45 ERA.

Ray is well-rested thanks to a 12-day break between pitching six innings July 6 at the Los Angeles Dodgers and six innings at Cincinnati on Tuesday.

The Diamondbacks planned a scenario where both Ray and fellow All Star Zack Greinke would be ready to pitch in the mid-summer classic, then get plenty of rest afterward.

"We had a good feeling that we were going to have those two guys in the All-Star game based on their numbers on and some of the things we were hearing," Arizona manager Torey Lovullo said. "We kind of set up the rotation to make sure that they were going to be ready (though) we weren't sure how much they were going to be used. These were two guys who have been dependable for us and consistent in logging a lot of innings."

So regardless of how much action they saw, they were going to get a long break. We felt that was going to be important. I've been preaching rest all year long. We want to play for as long as we possibly can this season. If we are going to play an extra month of baseball, that's going to play dividends for us."

Against the Nationals, Ray is 0-3 with a 6.48 ERA in three career starts versus the Nationals, the last one coming Aug. 2, 2016 when he gave up five earned runs in six innings.

Ray will also attempt to end Bryce Harper's 15-game hitting streak, which is the longest active streak in the majors. Harper hit his 25th homer as Washington evened the series with a 4-3 victory Saturday and is batting .463 during the streak.

Strasburg has made eight career starts versus Arizona, going 4-2 with a 3.28 ERA.

He is coming off a 6-1 victory over Cincinnati on Monday in which he allowed four hits and one run in seven innings. He struck out 11 and walked only one.

In matching up against the D-Backs, manager Dusty Baker said the Nationals are dealing with a potent lineup that can score in multiple ways.

"They got speed; they got power," Baker said. "In addition, the D-Backs left-right batter order makes for tough relief-pitching decisions late in games. When you're facing (David) Peralta, (A.J) Pollock and (Jake) Lamb and (Paul) Goldschmidt you go through your whole pitching staff trying to match up."

Baker also is trying to figure out how to use newly acquired relief pitchers Sean Doolittle and Ryan Madson. He recently sought out the advice of Bob Melvin, the pair's former manager in Oakland.

In addition to receiving Melvin's thoughts on how to best use the pair, the A's manager told him he was getting two of our best citizens and two of our best players. It's a great compliment when you get that from a manager.

The Nationals will close out a nine-game road trip in which they have gone 6-2, sweeping four in Cincinnati and splitting their last four games.