Quick, name the top two relievers in terms of WPA/LI… no, it isn’t Francisco Rodriguez. Not Brad Lidge, either. Brad Ziegler is a good guess, but sadly, no, he is not in the top two. If you said Mariano Rivera, kudos, because you’re getting warmer, but he comes in at spot number three. The top two relievers this year have been Hong-Chih Kuo of the Dodgers and Scott Downs of the Blue Jays. How many of you honestly guessed them? And, for the record, a guess does not involve hovering over the leaders tab, clicking ‘majors’, clicking ‘win probability’, clicking ‘relievers’, and then sorting by WPA/LI.

Kuo, a Dodgers lefty, leads all of baseball with a 2.35 WPA/LI, which basically means he has been worth almost two and a half wins more than an average relief pitcher. Downs, a Toronto lefty, has a 2.19 WPA/LI, close to Kuo, but still distanced by a good margin. To further clarify, Lidge ranks 13th at 1.36, Ziegler 17th at 1.34, and K-Rod 34th at 0.99.

While both pitchers have some statistical similarities, it seems they are getting their jobs done in different ways. Kuo has pitched in 40 games, three of which were starts, amassing 78.1 innings. He has allowed just 55 hits, only four of which left the yard. Additionally, his very low walk-rate—19 total in his 78.1 innings—has combined with the lack of hits to produce a 0.94 WHIP. He also strikes out a ton of hitters to the tune of 94 total and a 10.80 K/9.

Essentially, Kuo barely allows balls to leave the yard, barely allows baserunners, and strikes out many. Yep, I would say that is a formula for a tremendous relief pitcher. On the year, his 2.07 ERA is largely supported by a 2.20 FIP. His 79.8% LOB is great but not earth-shattering and is definitely sustainable, as we have seen elite relievers sustain very high strand rates. Kuo, who throws his 93 mph fastball over 80% of the time, is also more of a groundball pitcher, evidenced by his 1.48 GB/FB.

Downs, however, is MUCH more of a groundball pitcher. In his 61 appearances and 66 innings, just 11.9% of balls in play have been line drives, with 65% being hit on the ground. His GB/FB comes in at 2.88, almost double the rate of Kuo. Downs has surrendered just 47 hits, only two of which are home runs, but his walk and strikeout rates are not as dominant as Kuo’s. With 23 walks and 56 strikeouts, his 1.23 ERA vastly outdoes his 3.02 FIP.

Downs’ WHIP is higher as well, at 1.06, however he has stranded 89.9% of the runners that reach base; even though he allows more, he has stranded a much higher percentage than Kuo. I have heard and read Blue Jays fans hoping he could become a starter, but to do that he will really need to develop another pitch. At this juncture, he literally seems to use only a fastball and curveball, as both have accounted for just about 97% of his deliveries.

Kuo definitely seems to have the more sustainable and talent-driven line, but that should not take anything away from Downs’ effectiveness in relief this year. Both have been outstanding, and neither seem to garner the publicity they are due. Relievers are a fickle bunch, so who knows if they will be anywhere near the answer to this same question next year, but they have been rocks for their respective teams this season.