WASHINGTON -- All throughout the spring and summer, as Adam Wainwright 's right elbow defied him again and again, the right-hander maintained his desire to pitch again this season. Now that hope has become reality.

The Cardinals are planning to activate Wainwright and slot him back into their rotation next Monday for the opener of a three-game set against the Pirates at Busch Stadium. The assignment comes on the heels of a three-week rehab stint and will mark Wainwright's first big league appearance since May 17, when he landed on the disabled list with inflammation in the elbow.

Adding Wainwright to the rotation will initially bump Luke Weaver and Daniel Poncedeleon to the bullpen, though both remain candidates to make spot starts down the stretch.

"I feel like I'm getting called up for September," Wainwright said. "Earlier this season, I couldn't lift up a bag, pick up my shirt, after starts. I threw a bullpen after my last start, and I didn't know what would happen. And I felt normal."

Wainwright tested his elbow, which required surgery to remove cartilage and bone spurs last winter, incrementally over the course of the past month, making six appearances across three levels and eventually stretching out to 90 pitches. All told, he tossed 17 innings of scoreless rehab, including nine at Triple-A Memphis.

The 37-year-old, who is in his 13th season with St. Louis, had a 4.00 ERA in four starts prior to the injury.

"He's more than proven what he's done, how he's done it," manager Mike Shildt said. "He feels very comfortable, as well as we do, about being back to a highly competitive Adam Wainwright."

Where the Cardinals decided to place Wainwright is also telling. He could have slotted in as early as this weekend in Detroit but instead will be on seven days' rest when he toes the rubber on Monday. When he does, the Cardinals will have bypassed the chance to give rookie right-hander Jack Flaherty an extra day of rest. They still plan to do so as they monitor his innings, which have already eclipsed their previous career high.

However, the short-term benefit of keeping Flaherty on turn means the 22-year-old could start against the Dodgers, Braves and Brewers -- contenders all -- in the coming weeks. Sprinkling Weaver or Poncedeleon back in at some point appears likely -- the Cardinals will play 13 consecutive games starting Friday -- given the club's preference to manage Flaherty and Wainwright's workloads.

Roster move

The Cardinals added to their bullpen depth prior to Monday's series opener in Washington, recalling right-hander John Brebbia from Triple-A Memphis. Brebbia, who recently recovered from a strained right forearm, is 1-3 with a 3.83 ERA in 33 appearances for St. Louis this season. He gives the Cardinals a 30-man active roster and an 11-man bullpen.

Brebbia wasted no time making an impact, delivering a perfect inning in relief of Flaherty in the series opener vs. the Nationals.

On this date in Cardinals history

Seventeen years ago, 21-year-old Bud Smith tossed the last no-hitter in Cardinals history, against the Padres. Smith threw 134 pitches, walked four and struck out seven to complete the franchise's 11th no-hitter.

Joe Trezza is a reporter for MLB.com. Follow him on Twitter at @joetrezz.