MESA, Ariz. -- A’s right-hander Paul Blackburn drew the start for Thursday’s Cactus League-opening matchup with the Mariners, officially setting in motion a crowded competition for two rotation spots.

Blackburn, who gave up two runs in his lone inning of the rain-shortened exhibition, is among a long list of candidates vying to join a staff headed by veterans Mike Fiers, Marco Estrada and Brett Anderson.

“He’s definitely in the mix with all the other guys that we talk about,” A’s manager Bob Melvin said of Blackburn. “When he’s been healthy, he’s performed well for us, so he’s definitely in the mix of guys we would look to break with in the rotation.”

Weather conditions proved far from ideal for Blackburn, who was saddled with cold and the threat of rain. The A’s considered scratching the game in the morning but chose to forge on, allowing Blackburn to get his work in before play was halted after 1 1/2 innings and Oakland trailing, 5-0.

“You can’t control that,” Blackburn said. “I’m just happy to be back out there with everything feeling good.”

The right-hander was sidelined for all but a month because of two stints on the disabled list in 2018, beginning the season with a forearm strain and ending it with elbow lateral epicondylitis, commonly known as tennis elbow. He didn’t fare well on the mound, either, posting a 7.16 ERA with a .303 opponents average across 27 2/3 innings in six starts.

A year earlier, he opened eyes after earning a midseason callup, recording a 3.22 ERA in 10 starts before a fluke injury -- he took a liner to his pitching hand and suffered a severe contusion -- ended his season Aug. 23.

The A’s still think highly of the 25-year-old, who had plenty company on the sidelines last year. He was among the lucky, though, avoiding surgery unlike teammates Jharel Cotton and A.J. Puk, who underwent Tommy John surgery within a month of each other.

“Whenever you have elbow stuff as a pitcher, it’s kind of in the back of your mind,” Blackburn said. “Last year was the first year I really dealt with arm trouble, so I didn’t really know what to think. Little stuff would pop up here and there, and it would shift from the inside to the outside of my forearm. It was just about trying to be positive and not self-diagnose yourself.”

Blackburn allowed three hits on Thursday, limiting the damage with help from an inning-ending double play initiated by third baseman Chad Pinder.

“I’m actually happy about how everything went,” he said. “Coming into camp the last couple years, I’ve been leaving the ball over the middle, going glove side, and I think I had one that kind of came back over today and everything kind of stayed out there and got out to that corner, and that was kind of what I wanted to work on.

“Those first couple outings, I’m trying to get that four-seamer to stay on that side of the plate and not come back over, so today I was happy with the results I got out of that.”

Blackburn was deemed healthy in October, and he hasn’t stopped throwing since, wanting so badly to help these A’s continue what they started last year. To do so, he’ll have to stand out from a pack that also includes Daniel Mengden, Aaron Brooks, Parker Bridwell, Chris Bassitt, Frankie Montas and top prospect Jesus Luzardo.

“It was frustrating, stressful, just kind of every emotion,” Blackburn said. “Then coming out there today, it was a lot of fun. Just not being a part of what we were last year, it kind of sucks even looking at everything in New York with them playing a Wild Card Game. For me, that fueled the fire in me even more, just having a young, exciting team that’s hungry, and I just want to be a part of that, and I think that really helped a lot of people this offseason.”

Up next

• Mengden will get the ball for Friday’s 12:05 p.m. PT start against the host Mariners in Peoria, Ariz. Luzardo is also scheduled to pitch in the game.