Aledmys Diaz has gone from an unknown to a constant in two months with the Cardinals. (Alex Brandon/AP Photo)

On March 5, St. Louis Cardinals shortstop Jhonny Peralta fielded a ball in spring training and injured ligaments in his left thumb, a plight bad enough that surgery was required. Two weeks later, the Cardinals signed veteran Ruben Tejada, who had been cut by the Mets. But in the team’s final exhibition game, on the last day of March, Tejada strained a muscle in his leg, and spent opening day on the disabled list, not the field.

That day in Pittsburgh, the Cardinals started Jedd Gyorko, acquired in an offseason trade with San Diego, at shortstop – despite the fact that Gyorko is a second baseman by trade. In their second game, though, Manager Mike Matheny stuck a 25-year-old Cuban named Aledmys Diaz into the lineup.

“We didn’t really know what to expect,” Matheny said.

What they got was an offensive performance that has answered one question (Who will fill in for Peralta?) and forced them to ask others (What do we do when Peralta comes back?). Aledmys figured to spend the summer at Class AAA, where he ended last season. Now, he has become one of the best stories of the first two months of the season. Another good month, and he’ll end up in San Diego for the All-Star Game. Heading into June, Diaz is hitting .326 with seven homers and 25 RBIs; only two shortstops – Baltimore’s Manny Machado and Boston’s Xander Bogaerts – have a higher on-base-plus-slugging percentage than Diaz’s .903.

“I like to ask questions, you know?” Diaz said last week before a game against the Nationals in Washington.

As more Cuban players have gained higher profiles in the current game – none higher than Yoenis Cespedes of the Mets or Yasiel Puig of the Dodgers – there has been a growing discourse about how to better acclimate them to all aspects of American life, not just baseball. Puig’s struggles off the field last year, when teammates questioned his commitment, stemmed, the Dodgers now believe, from assumptions major league clubs make about players’ understanding of what’s expected of them.

Diaz’s inquisitive nature, then, has helped with his transition. When the Dodgers played in Los Angeles earlier this season, he and Puig discussed what each dealt with, both in the country in general and in clubhouses specifically.

“We talked a lot about the league, like, what he went through the first years he played in the majors,” Diaz said. “That helped me. I think it’s part of getting the feeling from your teammates. When you’re asking, ‘What happened? Why?’, that’s good.”

Much of Diaz’s questioning has been about preparation. Back home, where he began playing in the Cuban National Series as a 16-year-old, he said he played more by feel – which worked. As a 17-year-old in 2008, he hit .341; in 2011, his final season before defecting, he posted a .904 OPS with 12 homers in just 313 plate appearances.

Each day with the Cardinals, though, Diaz has learned to watch video of the opposing pitcher. He has learned to study.

“Here, you have to get a plan before the game,” Diaz said. “You have to know the pitcher you face that day. We don’t have the tools in Cuba that we have here. We don’t have the video. We don’t have the scouting report. You have to learn to take advantage of that.”

Diaz has, too, armed himself with another tool: English. After defecting from the Cuban national team during a tournament in the Netherlands in 2012, Diaz was barred from signing with a major league team until 2014 because he had lied, by less than a year, about his age. The Cardinals agreed to a four-year, $8-million contract with him prior to the 2014 season, which he spent at Class AA Springfield (Mo.). The Cardinals, like many MLB franchises, provide English support to their Latin players in the minors.

“The individual must be willing to do the work,” Cardinals General Manager John Mozeliak said in an email. “And Aledmys did.”

At Springfield, one of his teammates was Jonathan Rodriguez, a Puerto Rican-born first baseman.

“He helped me a lot,” Diaz said. “I realized I had to learn English to have a better conversation with my teammates and my coaches. It was important to me.”

Regardless of the language, Diaz has asked questions daily. Matheny said he saw veteran catcher Yadier Molina spending time with Diaz in the infield, reminding him that he actually has more time to make plays than he might realize – a worthwhile conversation, because Diaz’s struggles have been defensive in nature. He leads the majors with 12 errors. Even as Diaz was taking Tejada’s job – the veteran was cut by St. Louis late last week – Diaz went to him for instruction.

“The best way to learn is typically to be inquisitive and to figure out something that somebody else knows that you don’t know already,” Matheny said. “He’s humble enough to realize that there’s some great resources around here that have had more experience than he. He’s been a great student.”

With Peralta on a rehabilitation assignment and destined to re-join the Cardinals sometime soon, Diaz’s next learning period could be about a new position. Peralta, 34, has played 1,452 of his 1,671 major league games at short. Diaz has appeared in just one major league game at second, where the Cardinals are getting a .669 OPS mostly from Gyorko and Kolten Wong.

“I’ve learned about the adjustments you have to make here, you know – every day,” Diaz said. “You have to get a routine, get in here early, and prepare yourself for the game. … I have three years in this organization. I’ve been working with these guys, and that helps you feel like, ‘Okay, I can trust myself and go out there and play.’”