Circle Jack Flaherty's return date in pen.

The Cardinals' ace will make his much-anticipated return from his left oblique injury on Friday, when the club opens a three-game set in Kansas City, choosing that date with an eye toward caution since the designated hitter will keep the right-hander out of the batter’s box.

Otherwise, Flaherty is a full-go on the mound. With three rehab appearances under his belt, he's ready to put the first and only lengthy injury spell of his career behind him.

“American League game,” manager Mike Shildt said prior to Tuesday’s series opener against the Pirates. “Go get it.”

Picking Friday for Flaherty’s return was a marginal deviation for the Cardinals. Flaherty had expressed his desire to return for this current set in Pittsburgh, but since he aggravated his oblique tear while taking an at-bat on May 31 -- his last big league game back home in Los Angeles -- saving him until Friday will avoid any risk of injury that could come during an at-bat.

Flaherty injured his oblique while pitching, but he felt a more visceral tweak when swinging -- a tweak that’ll have kept him sidelined for nearly 2 1/2 months by the time he returns.

The Cardinals have already seen three starters go down injured this season while taking an at-bat -- Flaherty, Kwang Hyun Kim (who was placed on the injured list Monday with left elbow inflammation) and Carlos Martínez, whose torn right thumb ligament may have ended his season on July 4.

Flaherty started a hitting program at Busch Stadium on Saturday, a little too quick for the Cardinals to throw him back in the batter's box. His next turn in the rotation will assuredly come against an National League foe, likely the Aug. 19 series finale against the Brewers.

“He's just now in a hitting progression that would have kind of synced up where he would actually be more aggressive in that first time out,” Shildt said. “We didn't feel really comfortable with him being full-go. You can say what you want, ‘Oh, just go bunt.’ But the situation of the game dictates when you have to hit for him if he’s throwing well. We just wanted to be fair to him.”

Flaherty will slot into the rotation spot of Kim, whose outlook is murky. Behind Flaherty is Miles Mikolas, who is facing one more rehab start this weekend before he comes back the following week.

Mikolas’ return will give the Cardinals six healthy starters -- and some decisions to make about who remains in the rotation.

But that’s an issue for a later date, buried by the excitement of Flaherty's imminent return to the mound. No one is more amped than the 25-year-old, who was emotionally ready for his rehab to end long ago; it was only the second injury of his professional career, and his first of a lengthy duration.

Flaherty said he felt an issue creep in while he was pitching against the Dodgers on May 31, then felt the oblique strain when he took an at-bat in the top of the sixth inning. He did not return for the bottom of the frame.

All told, Flaherty appeared in three rehab starts, two with Triple-A Memphis and his last, on Friday, with Double-A Springfield, where he threw 75 pitches. The Cardinals rest assured in the fact that his injury was to the left side of his body, but they took a cautious approach as they worked him back into action.

Flaherty is set to not have any limitations on the mound when he pitches Friday. From a talent perspective, there were no limitations when he pitched at the outset of the year, leading the Majors in wins and seeming destined for an All-Star and potential Cy Young Award-caliber campaign when he went down.

Now all that’s left is to salvage -- and savor -- what he has left of it.