Cook, Chapman and dominance

Most of you are undoubtedly aware of the season Cincinnati Reds reliever Aroldis Chapman is having: In 21 appearances and 26 innings, his ERA is 0.00, he has 44 strikeouts and eight walks and batters are hitting .081 off him, with just one extra-base hit (a triple).

Chapman has allowed a run -- an unearned run against the Mets on May 17 thanks to a dropped fly ball. It's early, but Chapman has the ability to record one of the most dominant relief seasons we've ever seen.

Less heralded has been Oakland A's reliever Ryan Cook, who finally allowed his first two runs on Monday, blowing a 4-3 eighth-inning lead to the Twins in a 5-4 loss. Cook had gone 23 innings without a run. While he's been tough to hit -- opponents are batting .080 against him -- on one level hasn't matched Chapman's dominance, as his strikeout/walk ratio is actually a mediocre 21/14.

Cook came to Oakland from Arizona in the Trevor Cahill deal, and like Chapman he can light up the radar gun, averaging 95 mph on his heater and cranking it up to triple figures on occasion. In high school, Cook was as interested in race-car driving as baseball (his father is a drag racer). A scholarship to USC kept him focused on baseball, although with a career ERA of over 5.00 for the Trojans he fell to the 27th round of the 2008 draft. The Diamondbacks converted him to relief last season and he reached the majors for 12 appearances.

What has the work of Cook and Chapman meant for the A's and Reds? The A's are 16-1 when leading heading into the seventh inning -- Monday's defeat was the first game they've lost in the seventh, eighth or ninth inning after being ahead. The Reds are 17-3 when leading heading into the seventh, which sounds impressive, but actually isn't: that's an .850 winning percentage, which is actually lower than the major league average so far of .862.

(And, no, don't blame Sean Marshall: The Reds are 20-1 when leading after eight innings.)

I'm not dismissing Chapman's achievements here; the Reds are 4-0 when tied entering the seventh and 6-1 when tied entering the eighth. But that's more evidence that using your best reliever in high-leverage situations, like tied games, late in the game is arguably more important than using him in the ninth inning to protect a lead.