OAKLAND, Calif. -- You can call right-hander Kendall Graveman the Oakland A's last starting pitcher standing or, as manager Bob Melvin did Sunday, the Lone Ranger.

Graveman will make his team-high 22nd start of the season Monday against Baltimore, which is only fitting for the only member of the team's original rotation who has avoided a trip to the disabled list.

"He's been great and consistent for us, healthy, has a great work ethic," Melvin said before Sunday's 3-1 loss to the Cubs. "So it's nice to have at least one guy in the rotation that started the year."

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A's right-hander Sonny Gray (strained right forearm) was placed on the 15-day disabled list Sunday for the second time this season. He had an earlier DL stint with a strained right trapezius. Left-hander Rich Hill had two trips to the DL before being traded to the Dodgers. Chris Bassitt had season-ending Tommy John surgery, as did Felix Doubront, who was slated to be the fifth starter before being injured in the final exhibition game.

The A's current DL includes starting pitchers Jesse Hahn (strained right shoulder) and Henderson Alvarez, who has had two setbacks this year as he tries to come back from right shoulder surgery he had in July 2015. Right-hander Jarrod Parker is also on the DL. He had Tommy John surgery in March of 2014 and surgery for a fractured bone in his elbow in May of 2015.

"I've been fortunate," Graveman said. "Something I've never had to deal with is arm issues. Even in college. I take pride in being able to go out every day, every time it's my turn to go. It's tough to watch a lot of friends, a lot of teammates go through injuries."

Graveman (7-7) has set a career high for wins and will set a career high for starts on Monday. Graveman went 6-0, setting a career high for consecutive wins, with a 3.25 ERA, 34 strikeouts and 14 walks over 10 outings before struggling his past two starts.

Graveman allowed four runs (three earned) on six hits over 6 1/3 innings in a 5-3 loss to Cleveland on July 29. Then he gave up six runs over four innings and got a no-decision in an 8-6 loss to the Angels on Wednesday.

"Last week I thought I got out of the delivery that I'd been repeating for six, seven even eight weeks," Graveman said, "Just to get back to it in my bullpen this week was a positive. To be able to turn that leaf and say, 'Hey, I'm going to go back and not try to overthrow the baseball and get back to the regular sink in the bullpen and carry that over to the next game.' It's exciting. We've got another good team, another good hitting lineup coming in in Baltimore."

"You just got to continue to make pitches and you got to believe, as the old saying goes, that sometimes good pitches beat good hitters."

The A's were swept three games by the Cubs, who have the major-league's best record at 69-41, and fell a season-high 15 games under .500 (48-63).

The Orioles are 63-47 after a 10-2 victory Sunday against the White Sox. They lead the American League East by one game over Toronto.

The Orioles had five home runs Sunday, including three by third baseman Manny Machado, who became the second player in major league history to homer in the first, second and third innings of a game. He had a career-high seven RBIs.

"I've been trying to find my swing," Machado said. "This whole series, I've been squaring up some balls, which is fun, and today they finally went out of the park."

Right-hander Kevin Gausman will make his 20th start of the season for Baltimore. After a rough start against Toronto, he bounced back Wednesday in a 3-2 win against Texas. He allowed two runs on seven hits over seven innings, striking out seven and walking one.