Hendriks, a former starter, moved to the bullpen full-time in 2015 and responded with great numbers. In 58 games, he posted a 2.92 ERA (135 ERA+) with a rate of 9.9 strikeouts per nine innings and a 6.45 K:BB ratio. The Australian will be 27 years old next season, and he has four years of team control remaining (2016-19).
The key for Hendriks appears to have been the switch to relieving. As a starter, his strike-heavy style led to lots of hits and homers when MLB hitters weren't fooled by his mediocre stuff. As a reliever, pitching in shorter stints, he retained his control but was able to dial his velocity up from about 90 mph to the mid-to-high 90s. Here's a recent report from Chris Mosch of Baseball Prospectus:
Hendriks threw his heat nearly four full ticks faster than what it averaged out of the starting rotation from 2011-14, which is the third-highest velocity gain in the PITCHf/x era among pitchers who have thrown at least 200 fastballs as both a starter and reliever. Tommy Hunter and Daniel Bard are the only two pitchers who have experienced a more pronounced gap between their velocities as starter and reliever. The average pitcher in the sample gained about 0.9 mph of fastball velocity in the bullpen, so Hendriks' stuff played up significantly more than that of your typical bullpen convert.
Hendriks relies primarily on that now-much-faster fastball, as well as a slider that Mosch notes was up to 90 mph by season's end. If you're excited about failed starters rediscovering themselves as lockdown relievers, which I am, then this is exactly the kind of guy you're looking for. He could potentially slot in as a set-up man for Oakland.
Chavez, 32, will be a free agent after the 2016 season, so it always seemed likely that he would be dealt this winter. He pitched in 30 games this year, 26 of them starts, and posted a 4.18 ERA in 157 innings with a 2.83 K:BB ratio. Rosenthal says that he will fill a swingman role in Toronto, beginning as a long reliever but serving as a depth option for the rotation if needed.
Interestingly, when the A's claimed Chavez on waivers back in 2012 they got him from the Blue Jays. In the years since, they developed him into a quality pitcher capable of starting games, and now he's headed back from whence he came in exchange for a legit set-up man. If you want to get even spookier, the Jays traded away Hendriks in 2014 as well -- to the Royals for Danny Valencia! (Hendriks was traded back to Toronto a few months later.)
Rapid reaction: I love this trade. I will miss Chavez, who I had grown to like quite a bit, but I'm happy to trade one year of a good pitcher for four years of a different good pitcher. And while Chavez's versatility was useful, it's also nice to have someone with more upside in one role (lockdown reliever) rather than less upside in multiple roles (solid starter, solid reliever, solid longman). I was resigned to the fact that Chavez was going to be dealt, and I wanted to add some serious bullpen talent, so this move cashes in his value in exchange for a thing the team needed to find anyway. And, for what it's worth, Chavez will be available again next winter and says he wouldn't rule out a reunion with the team that gave him a real chance.
(Bluebird Banter, our Blue Jays team site, is not happy to have given up Hendriks in this deal.)
Strap in, folks, Mr.
Beane's Forst's wild ride is beginning.