ST. LOUIS — Vince Velasquez, so talented but so inconsistent, has been the source of excitement and frustration during his time with the Phillies.

It only took until the first week of May for new catcher J.T. Realmuto to fully experience the frustration that the right-hander can produce.

Realmuto was behind the plate for Velasquez’s start against the St. Louis Cardinals on Monday night. Velasquez gave up three home runs — two of them were two-run shots — in a span of seven batters as the Cardinals erupted for a 6-0 victory at Busch Stadium (see observations).

After the game, Realmuto voiced frustration that Velasquez did not follow his game-calling more.

“It definitely affected the game,” Realmuto said of Velasquez’s frequent shake-offs. “It's surprising. I don't really know, for some reason we couldn't get on the same page tonight. Obviously, it had an affect on the game. It's never good when a pitcher and catcher can't get on the same page. We've already discussed it. We talked about it right after the game. So hopefully we fixed it for next time.”

Velasquez walked too many batters and was too proud of his fastball. The Cardinals made him pay.

Fourth inning: Scoreless game. Velasquez walked Jose Martinez. The next batter, Yadier Molina, fouled off four pitches and worked the count to 2-2. Realmuto wanted either a two-seam fastball in off the plate or a breaking ball.

“I was fine with either one,” Realmuto said.

Velasquez shook to his four-seam, power fastball. Boom. Two-run home run.

The next inning, Matt Carpenter hit a 3-1 sinker for a solo homer. Two batters later, with a runner on first, Velasquez used his slider to get ahead of Paul DeJong, 1-2. DeJong then fouled off two four-seam fastballs.

“I felt like we had him set up pretty good for a breaking ball there,” Realmuto said. “It looked like he was on the fastball the whole at-bat. Again, Vinny had confidence in his fastball. He wanted to use it.”

Velasquez won the war of the fingers with Realmuto. He threw a 96-mph fastball and DeJong belted it for a two-run homer.

There were several reasons that the Phillies lost the game. Offensively, they had only five singles. They did not draw a walk. Miles Mikolas pitched very well with seven shutout innings for St. Louis.

Manager Gabe Kapler thought Velasquez’s five walks (one was intentional) w a huge factor.

But Kapler also conceded that Velasquez’s inability to put hitters away was also a factor.

That’s where Realmuto comes in.

The Phillies acquired him not only for his bat and his defense but for his ability to work with a pitching staff and call a game. Realmuto studies video and goes over the game plan with pitching coach Chris Young and the staff. It then becomes up to the pitcher to follow that plan.

And when the pitcher doesn’t follow the game plan, nights like this and performances like Velasquez’s happen.

“It's a little frustrating, of course,” Realmuto said. “Vinny has a ton of confidence in his fastball. That's one of the reasons he's so successful. It's a really good pitch. I'm sure he learned tonight that there are certain times where you need to go away from it and use something different. But you can't hate him for loving his fastball. He's just got to be a little bit more aware of about when to use it and when not to use it.”

Realmuto said he and Velasquez had meshed fine in previous starts.

“He's been pretty good this year,” Realmuto said. “I know he's had that problem in the past, but so far this year he's been pretty good with it. I'm not sure what the deal was tonight.”

After the game, Velasquez admitted he should have better followed Realmuto’s game-calling.

“I should do a better job trusting J.T. back there,” the pitcher said. “He does a great job studying the guys and knowing what works.

“I’m a power pitcher. I do try to put away guys with fastballs. I just have to learn how to balance and use the other pitches to throw guys off.”

Realmuto tried to take Velasquez there Monday night but the pitcher would not follow.

It will be interesting to see if he's learned anything from this when he next takes the mound Sunday in Kansas City.

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