Evaluating relievers is difficult given their small sample of work in any given year and their volatility from year to year. But, given the fact that the most active sector of the trade deadline ended up being relievers, it makes sense to put them all in one place and wonder who got the best one. Might there be a surprising answer since the Padres ended up holding Brad Hand’s production on their roster?

Here’s the full haul of relievers trading places Monday before the deadline, sorted alphabetically here.

Now that we have all of them in one place, we have to decide our metrics and time frames in order to evaluate them.

Velocity, This Year

Jeremy Jeffress is averaging 95.0 mph on his fastball this year, 94.6 on his sinker, and both numbers are second-best in the group. But that doesn’t quite tell the whole story about Jeffress, either — he’s lost two ticks on his fastball since last year, and in related news, he’s showing a career-worst whiff rate on his sinker, and a three-year low on his four-seamer. Velocity is good for grounders, too, but his sinker is getting the worst ground-ball rate that he’s shown. He’s not quite the reliever he was just two years ago, when he was at his best and in a Brewers uniform.

That’s also by raw numbers. Wilson’s 96.0 mph comes from the left side, and there’s a premium on lefty velocity. He’s your traditional radar gun king.

But there’s also effective velocity. Cingrani strides well compared to the shorter-striding Jeffress and Wilson. His perceived velocity is 94.5 to Jeffress’ 90.7 and Wilson’s 92.7. So the former Reds lefty with the big fastball and the long arms and the hardest slider of his career, that’s the guy that has the best velocity this season.

Spin Rate, This Year

Two pitchers stand out as having extreme spin rates in this group. Wilson has the 51st-best four-seam spin rate out of 314 qualifiers, and that’s helped him to nearly three times the average whiff rate on a fastball. Hernandez is decent, at 81-st best, but has been getting most of his whiffs this year from a new cutter.

Kintzler is actually the one with elite spin, though. Or lack thereof. He has the 170th-lowest spin rate on a sinker this year, out of 185. That’s helped him to standout 60% ground ball rates on his fastballs, and probably helps him in the next department.

Exit Velocity Allowed, This Year

Dave Cameron noticed an interesting thing about the Dodgers:

LA might as well name themselves the Exit Velocities at this point. Lowest EVs 1. Hill

2. Watson

6. McCarthy

8. Maeda

9. Wood

11. Kershaw — David Cameron (@DCameronFG) July 31, 2017

Watson does well by exit velocity, which has meaning in small samples, but can also be fickle and change quickly for any individual pitcher. Interestingly enough, Kintzler isn’t far behind in this metric, with a an 85.2 mph exit velocity allowed — three ticks better than average.

Tony Watson has excelled at limiting exit velocity. (Photo: Keith Allison

Whiffs, Last Three Years

Now that we’re headed into results, let’s up the sample to get more results. Would you believe that Watson is second on the list? It’s worth pointing out that he’s fifth this year — Hernandez moves from second to first if you zoom in on this year, and Reed and Smith end up second and third, respectively.

But if you want a reliable source of whiffs, Watson has been your man behind Wilson. Who knows why the difference between Watson’s change-up and fastball has slimmed to a career low, causing him to lose whiffs recently. Maybe he can fix that and get back to where he was.

Ground Balls, Last Three Years

If you want a ground ball, you want Kintzler. That low-spin sinker deadens the exit velocity, and his ability to hit the outside corner against righties has helped him lead this group in ground ball rate over the last three years. And it’s not just impressive among this group, either — Kintzler has the 14th-best qualified ground ball rate among all relievers over the last three years.

Jeffress deserves some love here, too. Ever since he went to the sinker more than the four-seamer due, perhaps, to recognizing that his average spin would play better on the sinker, he’s been a reliable ground ball guy.

Strikeouts Minus Walks, Last Three Years

Especially during a time in which balls in play are volatile, it’s often best to limit results to the the most basic, pitcher-controlled statistics. Does he strike out a lot of guys and walk very few? Then what you’ve got is Reed, whose 20.4% K-BB% leads this group (with Wilson) by a fair margin and ranks 31st in baseball among qualified relievers over the last three years. In New York, Reed upped his arm angle, recovered the ride on his four-seamer, and fiddled with his slider in order to limit walks and show the best two strikeout minus walk rates of his career. But for Mets fans who wanted a better return for a player that has a better strikeout minus walk rate these last two years than Cody Allen, it’s worth pointing out that Reed’s velocity is down this year, and for a reliever that has been fairly volatile, that is at least one red flag.

One-Handed Dominance, Three Years

Perhaps you only really want your reliever for a certain situation. That is, after all, how they get their most work in. Of course, we don’t want to re-do this entire list for each handedness matchup, so let’s just use the hammer that is FIP (Fielding Independent Pitching) to judge dominance in this category.

Best Platoon Splits for Deadline Relievers Name Team K% BB% K-BB% HR/9 ERA FIP Addison Reed vs R 27.1% 4.0% 23.1% 0.76 2.62 2.56 Justin Wilson vs L 27.2% 7.6% 19.6% 0.52 4.50 2.64 Addison Reed vs L 23.4% 6.6% 16.9% 0.47 2.49 2.68 Tony Watson vs L 22.0% 5.3% 16.7% 0.32 1.13 2.78 Joe Smith vs R 24.7% 4.7% 20.0% 0.63 3.35 2.83

Reed is great because he doesn’t have crazy platoon splits and can get lefties and righties out and strikes everyone out and walks nobody. He’s probably your ‘best’ reliever that was traded at the deadline — Wilson’s 3.18 FIP against righties shows a bigger split between hands.

On the other hand, Wilson is dominant against lefties. And Smith has that arm slot that is tough on righties, but also admitted to me earlier this season that he was throwing the four-seam more than ever “because now even righties have the swing to lift the low pitch because of launch angle and homers and getting paid,” and that you “have to be able to pitch in on guys.”

In certain situations, you need certain things. Reed is a great set-up man that you can just pencil in against either hand, so he’s probably the ‘best’ reliever traded near the deadline. But let’s make sure.

Projections, Rest of Season

One more table just to make sure.

Rest of 2017 Depth Charts Projections, Deadline Day RPs Player IP ERA FIP WAR Addison Reed 24 3.58 3.43 0.4 Joe Smith 23 3.40 3.59 0.3 Justin Wilson 20 3.52 3.30 0.3 Brandon Kintzler 24 4.00 4.08 0.2 Tony Watson 19 3.76 3.98 0.1 David Hernandez 12 3.58 3.68 0 Jeremy Jeffress 11 4.33 4.48 0 Tony Cingrani 14 4.75 4.92 0

The margins are razor thin, as they almost always are for relievers, but nothing here refutes that Reed was indeed the best reliever traded today. Of course, it’s not that simple — game situations will dictate the usage of each pitcher, as will the composition of each of their new teams. Facing a lefty? Tony Watson and Justin Wilson have been lights out against them for a while now. Facing a righty? Time to get Joe Smith, who is nasty against righties. Need a ground ball? Brandon Kintzler is the master.