Champ or Chump: Ken Giles and Roberto Osuna

This column doesn't usually venture into relievers, as I generally believe that their small sample sizes and dependence on saves (a stat that basically measures how much a manager trusts a given guy for whatever reason) make a quantitative analysis moot. However, I (and many others) have struggled with Houston's decision to give up real value in order to acquire Roberto Osuna, a pending legal case in the Canadian justice system, and one of the worst PR backlashes baseball has seen in years.

I am not a lawyer, and have no particular insight into the legal part of the case save that Osuna's hearing has been pushed back to September 5 and MLB saw fit to suspend him for a long time. I am a fantasy baseball analyst, so let's see if this trade makes sense from a baseball standpoint assuming nobody covered below ends up in prison.

Spoiler alert: it doesn't.

The Fantasy Jury is Out

Ken Giles (RP, TOR) - 45% Owned

On the surface, Giles has been a terrible reliever this year. His K% (24.8%) is much lower than his career rate (32.6%), and his ERA stands at an unsightly 6.29 as of this writing. However, his peripherals suggest that he hasn't completely lost it. His BB% fell with his K% (2.7% vs. 7.5% career), and his xFIP is a reasonable 3.35. That's still not as good as either metric was last year (2.30 ERA, 3.09 xFIP), but it's not bad enough to doom a fantasy team either.

My gut reaction was that Giles was experiencing especially poor luck, but there seems to be something to his struggles. Last year, batters hit .198 against him and deserved a slightly lower but comparable xBA of .189. This year, batters are hitting .306 against Giles and deserved a slightly lower but comparable xBA of .287. Slugging percentage tells the same story, as this year's .500 SLG and .493 xSLG are way higher than 2017's .297 SLG and .289 xSLG.

Giles only throws a two-pitch mix, so there aren't many suspects for his problems. His slider is traditionally an excellent wipeout pitch (27.4% career SwStr%, 49% chase rate, 37.3% Zone% career) and is performing similarly this year (27.8% SwStr%, 46% chase, 41.5% Zone%). Its batting average against is slightly higher due to its increased Zone% (.186 vs. .132 career), but that's far from bad. His slider is not the issue here.

That leaves one option: the fastball. His heater's Zone% is up (60.9% vs. 55.3% career), while its velocity (97.3mph vs. 98.2mph last year per Statcast), perceived velocity (95.42mph vs. 96.53mph last year), and average spin rate (2,379 RPM vs. 2,455) are all down. The difference can be seen in his results, as last year's .283 BAA has increased by over 100 points to .388.

It's not trending in the right direction, but the 28-year old should be too young to suddenly lose it barring injury. It's possible that a simple mechanical adjustment is all it will take to get Giles back into 2017 form. All of the Statcast metrics above are solid if you pretend that they weren't higher in the past, so Giles should be able to adapt even if this is the new normal.

Giles isn't working the ninth for Toronto yet, but all reports suggest that the plan is to use him as a closer. With K% upside in excess of 30%, he could be the perfect relief arm to roll the dice on if you need an RP down the stretch.

Verdict: Champ

Roberto Osuna (RP, HOU) - 80% Owned

Osuna only has 18 1/3 IP on the season thanks to his suspension, pitching to a 2.45 ERA and 3.64 xFIP in that time. Most news outlets have taken Osuna's "elite" status as a baseball player for granted when reporting the trade, but it's not clear that he deserves that moniker.

Like Giles, Osuna's K% fell off of a cliff (19.2% vs. 28.8% career) this year. His BB% has also declined to a minuscule 1.4%, but it's not worth the K% decrease considering his career rate is already an excellent 4.5%. The reason why is as simple as looking at his pitch mix.

Unlike Giles, Osuna uses a five-pitch mix. His fastball usage is way higher this season (31.3% last year to 56.3% this) at the expense of his cutter (27% to 17.1%), sinker (16.5% to 10.4%), and slider (20.6% to 11.7%). He also throws a show-me change 4.6% of the time, but the sample is too small to do anything with.

Osuna usually starts with a fastball, so we will too. It's pretty good, producing a 10.4% SwStr% and 64.4% Zone% on the season. It's not typically thrown for a strike that often (57.5% Zone% career), causing it to induce whiffs at a slightly lower rate than its career mark (12%). Still, it's a solid building block for a dominant arsenal.

However, Osuna's cutter is probably better. While not a strike quite as often (53.7% Zone% this year, 44.5% career), it induces whiffs at a much higher rate (14.6% SwStr% this year, 17.7% career). Osuna's heater has been much better when put in play in this season's small sample size (.212 BAA vs. .385 for the cutter), but the opposite was true last year (.259 vs. .241).

It also generates ground balls (50% GB% career, 54.5% this year), something that Osuna's heater doesn't really do (32.1% GB%). Osuna's career FB% is 41.8%, a little on the high side when the game is on the line. Throwing more cutters last year brought that number down to 34.2%. It's actually an even lower 30.9% this year, but all of the missing flies have turned into line drives (30.9% LD% vs. 20.3% career). He's back to allowing a ton of airborne contact, something not expected of an "elite" fantasy closer.

Osuna's slider is his signature pitch, generating a 27.2% SwStr% and 46.8% chase rate over Osuna's career. Its whiff rate is down in 2018 (17.9% SwStr%), but an exceptional 50% chase rate suggests that it remains as effective as ever. However, Osuna is throwing it half as often as he used to. Elite closers do not look for reasons to avoid throwing their best pitch.

Osuna's sinker is terrible when compared to his fastball or cutter, so add his name to the lengthy list of pitchers who throw a sinker but probably shouldn't. He's definitely good, but last year's 3.38 ERA (and 2.57 xFIP) fall short of elite status. Heck, Giles beat him in ERA by a substantial margin last year and he lost his job for a stretch.

Osuna is a mid-tier fantasy closer on his best day, with recent pitch mix changes serving to limit his upside. Add in a real possibility of spending time in a Canadian prison, and you have to wonder what the Astros were thinking.

Verdict: Chump

More 2018 Player Outlooks