Signed by the Nationals for $20,000 out of the Dominican Republic in 2011, Mercedes played three years in the Rookie-level Dominican Summer League before getting released and spending 2014 in a pair of independent circuits. After hooking up with the Orioles, he toiled for three years in their system before the White Sox grabbed him the Minor League phase of the Rule 5 Draft at the 2017 Winter Meetings. He posted a 1.033 OPS in the final three months in Triple-A last season to finally claim a spot on a 40-man roster in November.
Mercedes may be older than most prospects at age 27, but he has hit almost everywhere he has gone in pro ball and compiled a .302/.366/.491 line in his first eight seasons in the Minors. He makes consistent hard contact to all fields from the right side of the plate, generating most of his fringy to average power to the pull side. He controls the strike zone well, mashes left-handers and holds his own against righties.
Mercedes also possesses a plus arm behind the plate and a long track record of erasing basestealers, including 44 percent in 2019. He's a very shaky receiver, however, which detracts from his ability to catch on a regular basis even though Chicago likes his framing metrics. His lack of speed limits his ability to play other positions, though he did get brief action at first and third base last season.