Emmanuel Rivera was drafted in the 19th round of the 2015 MLB Amateur Draft out of a San Juan college on Puerto Rico. Not the most common college where you’d pick a possible MLB talent from, but apparently he didn’t really stand out in his high school years and wasn’t able to get a scholarship from an American University.
Being a 19th round pick, expectations were probably low, and Rivera indeed struggled quite a lot after coming over to the States: in 2015 he struggles to a .534 OPS in the complex league and in 2016 to a .