Báez, who had the MLB logo tattooed on the back of his neck when he was 16, entered the league stuffed with confidence and potential. But he only intermittently made good on that promise. Though he had a torqued, dangerous swing, a quick glove, and an arm that seemed somehow hydraulic, he suffered from the prodigy’s overabundance of opportunity and struggled, at first, to put it all together. He’d hit a towering home run (such as the 12th-inning game winner in his MLB debut) and then strike out in droves (he whiffed 95 times in 52 games his first year). His spectacular defensive plays were sometimes offset by his fumbling of standard ones. During his rookie season, he batted just .169. The next year, bothered by a finger injury and further strikeout issues, and heartbroken by the death of his sister, he spent most of his time back in the minors, playing only 28 big-league games.

Prior to the 2016 season, Joe Maddon, the Cubs’ outside-the-box manager, hatched a plan: Báez would stay with the Cubs full-time, applying his already evident adaptability as a backup all around the infield and working to improve his discipline at the plate. “I don’t think it’s going to be overwhelming at all to him,” Maddon said of a role that could be construed as too daunting for such a green player. “I think he actually kind of likes it.” The hunch proved accurate; Báez took it as his credo to “play the best defense I can.”

He quickly emerged as a favorite of Cubs fans and baseball aficionados alike for his surreal glove work—whirling one-man double plays, hyper-reflexive ground-ball picks—and turned into a steadier, if still not wholly consistent, hitter. During the Cubs’ curse-breaking 2016 championship run, he was named co-MVP of the National League Championship Series. A few months later, when he played on Puerto Rico’s World Baseball Classic team and earned all-tournament honors, his tagging ability became a minor phenomenon. A particularly GIF-able moment came when he pointed to the catcher Yadier Molina in celebration before Molina’s throw had even reached his glove, and then, an instant later, swiped the base runner blind. He earned the nickname El Mago, Spanish for “the magician.”

The 2018 season has marked another major shift for Báez, from cult hero to full-fledged franchise player. Part of it is the simple individual progress that tends to come with maturation; his batting average, on-base percentage, and slugging percentage are all the highest of his career. But the more interesting part is that his skill set has been exactly what the Cubs have needed in a year rife with complication. When the former MVP Kris Bryant went on the disabled list with a shoulder injury in midsummer, Báez stepped in to assume some of his third-base duties. After the second baseman Daniel Murphy arrived to the Cubs in a mid-August trade, Báez forsook his most common position to make room for him. Most recently, when the shortstop Addison Russell was accused of domestic violence and placed on administrative leave, Báez took over, providing much more than a stopgap at the crucial infield position.