CINCINNATI -- Throughout this season, and in the second half of 2018, Reds ace Luis Castillo could often appear supernatural on a mound -- especially with his masterful changeup. On Friday vs. the Cardinals, Castillo was a mere mortal and unable to do anything that fooled hitters.

In what was arguably the worst start of his career during a 13-4 loss to St. Louis, Castillo gave up a career-high eight earned runs and tied a career high with nine hits allowed over 4 1/3 innings and 93 pitches. Entering the night, only three of his 15 homers allowed this season came with runners on base. The Cardinals matched that total in one night at Great American Ball Park.

• Box score

St. Louis hitters were poised to work tough at-bats vs. Castillo from the beginning. He threw 31 pitches in the first inning and allowed just one run, but three of the five hitters saw six or more pitches. 

“He’s one of the best in the game,” Cardinals second baseman Kolten Wong said of Castillo. “You have to approach the guy with the respect and just try to wear him out. I think we had a lot of tough ABs, and when you’re constantly putting pressure on them, eventually they’ll make a mistake.”

Castillo was one pitch away from having a clean second inning when Wong tapped an 0-2 pitch for a soft floater past third baseman Eugenio Suarez -- who departed the game early with a left thumb sprain -- and inside the left-field line for a single. Pitcher Adam Wainwright followed with a single. With Castillo mired in a 3-0 count, Dexter Fowler pounced all over a fastball and crushed it to right field for a three-run homer, giving the Cardinals a 4-0 lead.

“In that situation, I just want to throw a strike because I want to get back into the count,” Castillo said. “That happens when you fall [behind] in the count every time. You just have to throw pitches around the zone for the hitters to swing and you work the count again. I think that happened with the homers, like 3-0, I have to throw the ball over the middle of the plate.” 

In the third inning, Paul DeJong lifted an 0-1 slider for a two-run homer to center field, before Castillo retired the next five batters in order. Trouble returned in the fifth when Tommy Edman led off with a single and Paul Goldschmidt went from an 0-2 count to 3-2, before he sent a fastball into the right-field seats for a two-run homer.

Entering the night, Castillo was 2-0 with a 1.13 ERA over his previous four starts vs. St. Louis.

“A lot of us haven’t had -- well, the league hasn’t had much success against him,” Fowler said. “We got some good pitches to hit and put them in play.”

Cincinnati’s rotation has been a strength all season and came into play Friday ranked third in the National League in ERA (3.96). That mark was at 3.60 at the All-Star break. But two of the club’s top starters -- Castillo and Trevor Bauer -- have been roughed up in the last three games. Bauer gave up a career-high nine earned runs over 4 1/3 innings -- including eight in the fifth -- during a 17-7 loss to the Nationals on Wednesday.

• Aquino continues to bludgeon HR record books

“At this time of year, these guys have been pitching for a long time,” Reds manager David Bell said. “I really feel good about the health of our starters. There’s no injuries and we’ve managed their pitch counts and innings pretty well. That’s been a thought too, that they're strong. There’s not a lot of off-days coming up and we haven’t had a lot. Other than that though, we know they’ve been through this before, so they’ll be back.”

Although Castillo trailed Hyun-Jin Ryu of the Dodgers, Jacob deGrom of the Mets and Mike Soroka from the Braves in National League Cy Young Award consideration, Castillo certainly could have made a bid of his own with a strong final six weeks. Friday certainly put a rather large dent in those hopes.

Now 11-5 in 25 starts, Castillo has watched his ERA jump from a stellar 2.69 to 3.10 for the season.

“With Luis out there, we felt good,” Bell said. “Everybody is going to have a night like that, and he’s been pitching so well. It looked to me like he was missing over the middle of the plate a little bit and they were ready for it.”