They are different as can be.
One a veteran, the other a rookie. One a lefty, the other righthanded. One a soft-tosser, the other capable of high octane.
And for the foreseeable future, they are tied at the hip. When one is through pitching, it's time for the other to take over. All that's missing is a baton.
Rich Hill started Tuesday's 5-3 win over the Detroit Tigers and Garrett Whitlock finished it, and if the Red Sox have their way, that will happen another 30 or so times the rest of the season.
It's an usual strategy, but then, these are unusual times. And a compressed spring training has made it stranger still. Most pitchers aren't adequately stretched out early in the season, so this plan helps mitigate against any worries about over-taking the starting rotation in April.
But this isn't designed solely for the first month. The Red Sox, who began drawing up this plan as soon as they signed Hill last December, see this as beneficial on several fronts.
There was no arguing with the results on Tuesday. Hill set down the Tigers in order in the first two innings before a combination of bad luck and an inexperienced right field conspired to result in three runs against him in the third. Christian Arroyo, who had never started a major league game in the outfield until Sunday night in the Bronx, approached two balls in the way you might expect from an inexperienced outfielder.
On one, he got his glove on a ball in the gap, only to have it fall in for a double for rookie Spencer Torkelson. Three batters later, he took a circuitous route to ball near the right field foul line and was unable to glove it as it fell in for run-scoring single for Jonathan Schoop. It was, to borrow a phrase from former Red Sox manager Jimy Williams, an example of "buzzard's luck,'' for Hill, but he managed to strand Javy Baez in scoring position and limit the damage.
He got through the fourth, unscathed, despite another miscue from his outfield -- a throwing error by Alex Verdugo placed a runner on third -- but again pitched out of further trouble. After retiring the first hitter in the fifth, a one-out walk, and a pitch count at 70 conspired to end his afternoon.
But wanting Whitlock to have a clean inning when he entered, the Sox tabbed Hirokazu Sawamura as an intermediary, who had the good sense and efficiency to throw three pitches and record two outs, thanks to some inattentive baserunning on the part of Robbie Grossman.
Then came the sixth, and enter Whitlock. A biggest contrast to Hill you could not find. Whereas Hill alternates between a 1980s fastball, topping pout at 89 mph, and a slow, breaking curve, Whitlock offers a heater than can hit the upper 90s, augmented by a slider and changeup.
It's literally true that, from a pitching standpoint, the two have nothing in common when it comes to pitching - other than the fact that both, as required by law, throw from a distance of 60 feet six inches from the plate. The commonalities end there.
And that's part of the attraction. Just as hitters have to slow their bats to not overswing against Hill's lollipop of a curve or his sub-average fastball, they need to speed things up to catch up to his fastball, or protect the outside of the plate for his horizontal slider.
Hitting, it's been famously noted, is about timing and pitching is about disrupting that timing. With Hill first, followed by Whitlock, the Red Sox have an automatic ball of confusion ready for opposing lineups. Just when they've timed the 12-6 curveball and BP fastball of the veteran, they have to gear up for the velocity and sweep of the second-year pitcher's offerings.
"There's a reason we like them together,'' said Cora of the duo. "They're going to load up with righties against Rich, and he can get them out and then we turn the page to Whitlock and get a lot of good matchups. They compliment each other well. It's a good plan.''
Baseball has uncovered a slew of new pitching concepts in recent seasons, from the idea of the opener, to the return of the multi-inning reliever. Now, add the concept of the tag team to the novel ideas. Teams are more than willing to be innovative if it means finding a way to get 27 outs.
The appeal here, of course, is to limit the innings for Hill, who began the season as the game's oldest pitcher and whose 158.2 innings last year were the most he's thrown since 2007. If they can get somewhere near 150 again -- or 30 starts, at five innings a crack -- they'll be more than content.
As for Whitlock, in a perfect world, he'll eventually transition to the rotation. But this role serves as a nice platform toward that transition. The key will be to determine how to best use him one of one of the other four days. For this, is a more efficient use of his abilities than, say, closing.
Knowing that he has Whitlock to contribute bulk innings and get to the finish line, Cora can go all-in the day before the two pair up. And, the day after, the rest of the bullpen is well-rested.
There's no guaranteeing this approach will work throughout the season. Injuries and under-performance could break up the partnership and require adjustments.
But first time out, there was no arguing. The Odd Couple worked like a charm.