Jeff Passan of ESPN reported Hendriks' deal features $39 million over the first three years, with the reliever set to receive $15 million whether the White Sox exercise the fourth-year option or opt for the buyout:
The 31-year-old spent three seasons as a middle reliever for the A's before he was elevated to the closer role following an injury to Blake Treinen in June 2019, and he's been virtually unhittable ever since.
Hendriks has posted a microscopic 1.79 ERA and 0.90 WHIP with 39 saves in 99 appearances since the start of the 2019 campaign. He leads all relievers in WAR (5.2) over that span, and his strikeout rate (13.2 per nine innings) also puts him among MLB's elite, per FanGraphs.
By comparison, the Australian right-hander's career ERA stands at 4.10 through 344 games. It was only a modestly better 4.01 during his first three years with the Athletics.
His sustained improvement led to his first All-Star selection in 2019 followed by the American League Reliever of the Year Award in 2020. He also finished ninth in AL Cy Young Award voting last season.
In between three years with the Twins (2011-13) and five years with the A's (2016-20), Hendriks had two stints with the Toronto Blue Jays in 2014 and 2015 sandwiched around a brief stop with the Kansas City Royals.
Though he entered the offseason as one of the league's top free agents, he told Brodie Brazil of NBC Sports California he planned to take a mostly laissez-faire approach to the market.
"I told my agent, 'You deal with it all but let us know who's reached out and in what order,'" Hendriks said in November. "Kind of let us know what they're saying. I like to have an idea of what's going on."
The 2020 All-MLB first-team selection decided the White Sox were the best fit for him. Expectations will be far higher following the move than when he arrived in Oakland, but his electric fastball-slider combination and the rising importance of relievers make him a major addition.
Hendriks should slot in as the club's closer to open the 2021 season, with Aaron Bummer, Evan Marshall and Codi Heuer bridging the gap to the ninth.