The biggest surprise came next.
"Frankly, we didn't think Oscar was going to get to our pick at 57," Kantrovitz said of the Cardinals' second-round selection, high school shortstop Oscar Mercado. "When you see a shortstop of that caliber still on the board at 57, we weren't going to walk away."
Mercardo, an 18-year-old out of Vivian Gaither (Fla.) High School, rounded out the organization's Day 1 picks and left the Cardinals especially thrilled with the start of the three-day, 40-round Draft.
"It's a really exciting group," Kantrovitz said. "Arguably, we got three first-rounders today."
With Mercado, the Cardinals get a young player who projects to stay at a premium middle-infield position for the long-term. He is considered defensively advanced for his age, with Kantrovitz describing him as "fluid," his arm as "above average," and his hands as "slick."
The Cardinals also believe his sagging offensive numbers -- perhaps one reason why he dropped as far down as he did -- as a high school senior are not indicative of his future potential. Mercado hit .286 with only five extra-base hits during his senior season. He had a much better offensive showing at the East Coast Pro Showcase last summer and as a junior, when he batted .370 with 29 RBIs and 12 stolen bases.
"We saw him a lot over the summer against some of the best pitchers in the country, and [he] actually hit pretty well," Kantrovitz said. "In the same way that we don't read into the stats of a high school player on the really positive end, we don't read that much into a high school player's stats on the negative end.
"We think Oscar is going to surprise some people with the bat. But at the same time, we're going to have to be patient with him. He's not a guy that we are going to expect to fly through the system. He's a young high school player that we're going to take our time with and groom, and hopefully he develops at the pace we think he's going to."
Mercado was born in Colombia and immigrated to the United States at the age of 8. He is slated to play collegiately at Florida State University, so the Cardinals will have the challenge of trying to lure Mercado away from commitment. While it may take offering more than the assigned slot value for the 57th pick ($971,400), the Cardinals expressed optimism on Thursday that they will be able to convince Mercado to sign.
That confidence is largely based upon intelligence gleaned through discussions with Mercado prior to the Draft.
Who the Cardinals selected on Thursday will play a role in their strategy on Day 2 of the Draft, which will feature third- through 10th-round selections. Each of those Day 2 picks will count against a team's total pool of Draft money, which for the Cardinals totals $6.9079.
Because the organization made a pair of aggressive high-school selections on Thursday, it will look to complement that by drafting some players on Friday who the Cardinals believe can be signed for less than the slot value. That will help to balance out the overall money pool.
"It doesn't handicap us by any means, but definitely by being as aggressive as we were tonight, it means that we're going to have to be cognizant of that tomorrow and not overstep our boundaries when it comes to the cap," Kantrovitz said. "My guess is what you'll end up seeing is a healthy mix of some cost-certainty picks, whether that's in the form of some college seniors mixed in with some higher-ceiling guys."
Day 2 of the Draft continues with Rounds 3-10, streamed live on MLB.com on Friday, beginning with a preview show at 11:30 a.m. CT. And Rounds 11-40 will be streamed live on MLB.com on Saturday, starting at noon.
MLB.com's coverage includes Draft Central, the Top 100 Draft Prospects list and Draft Tracker, a live interactive application that includes a searchable database of Draft-eligible players. You can also keep up to date by following @MLBDraft on Twitter. And get into the Draft conversation by tagging your tweets with #mlbdraft.