ST. LOUIS -- All of a sudden, Miles Mikolas, who distinguished himself in 2018 with his high volume of ground-ball outs and efficient innings, has been bitten by the long-ball bug.

Three more home runs -- these by the Reds, who hit a total of five en route to snapping the Cardinals’ five-game winning streak with a 12-1 rout at Busch Stadium on Friday night -- swelled his season total to eight. That’s how many home runs Mikolas had served up after 20 starts last year. This season, the barrage of blasts have come in six appearances (34 innings).

“Sometimes you leave balls down the middle, and they are flyouts to center. Sometimes they are home runs,” Mikolas said after a game in which the Cardinals allowed a season high in runs and hits (14). “Everyone is joking saying the balls are juiced. I just think if you leave pitches middle, it’s not a good place to leave them.”

Trouble started quickly for Mikolas. Eugenio Suarez took the right-hander deep on his 11th pitch of the night. Leadoff homers by Jesse Winker and Joey Votto in the fourth and fifth innings, respectively, helped the Reds build their lead.

It marked the fourth time in five games that the Cardinals have surrendered at least three home runs. Their offense, which was held below two runs for the first time this season on Friday, has alleviated that long ball sting all season -- though that’s not likely to be a sustainable model for success.

It has helped, too, that of the 51 home runs (a National League high) the Cardinals have allowed, 35 have been solo shots.

“Again, we don’t love a solo homer, but it’s a lot better than the alternatives with the homers,” manager Mike Shildt said. “It’s a trend that I’m sure will dissipate shortly. “

For Mikolas, the jump in home runs is particularly noticeable. Tabbed as the Opening Day starter as a nod to his stature as staff ace, he has now lasted only five innings in four of his six starts. The common thread in those outings? In each one, he’s been taken deep.

A deeper study of those eight home runs hit off Mikolas reveal that they’ve come on two pitches – four on his two-seamer and three on the slider. (The other, which was also hit by Winker, came in the Mexico Series, where there was no pitch tracking available).

He’s using the pitches, according to Statcast, at a percentage similar to a year ago. But the contact is harder and his command, not so crisp.

Entering Friday, opponents had registered an 88 mph exit velocity on Mikolas’ two-seamer, up from 85.7 mph a year ago. The exit velocity on his slider has jumped from 84.3 mph to 89.5 mph.

The result has been more hits, and, in particular, more hard hits. Mikolas already has allowed as many homers on his sinker as he did in 32 starts last season. He’s also only three extra-base hits shy of matching that total, too.

As for the slider, it’s a pitch that opponents took deep just once in 2013. In these six starts, it has resulted in five extra-base hits, including the three homers.

“I wouldn’t say I’m trying to find those [pitches],” Mikolas said. “Just didn’t get the [two-seamer] to Winker down. The slider to Votto, just trying too hard to get ahead, I think. Those might have been the only two real bad pitches I threw all day, and I had to pay for them.”

Execution of the two pitches has routinely been the culprit, as the accompanying Statcast pitch charts -- the first showing the home runs allowed in his first five starts, the second displaying the Reds’ run-scoring hits on Friday -- indicate. Too often, Mikolas has left his sinker and/or slider high and centered over the plate.

One byproduct of that has been more balls in the air. His fly-ball rate has jumped from 18.8 percent in 2018 to 28.6 percent in '19, and the launch angle off his sinker has soared from 5 degrees to 15.

“I just think he’s getting too much of the plate,” Shildt said. “He’s getting the ball up, out over the plate, and guys were able to get swings on him. He made a lot of good pitches tonight. Solo homers got him. Just some mistakes that didn’t come back.”