They have to hope they are the ones who benefit from the reduced number of oxygen molecules in the rarified air, and they have to pray the Boston Red Sox suffer from the lack of an important element in their team chemistry.
Don't fret. I'm not going to blind anybody with science. It's just that both teams will arrive at Coors Field for tonight's Game 3 with plenty of room to wonder how the change of environment will affect this - so far - one-sided exercise in American League superiority.
The Rockies should gain some advantage - and maybe regain some confidence - playing at a more familiar altitude, but other teams have been known to score a few extra runs up here, too.
Much has been made of the fact that the once-outlandish offensive numbers generated at Coors Field have been tempered since the Rockies began to store the baseballs in a humidor, but the thin air still can have a major effect on pitchers who rely heavily on breaking stuff.
That could present a challenge to Red Sox starter Daisuke Matsuzaka, who complements his fastball with a variety of sharp breaking pitches.
"I think pitching at altitude, it is what it is, but you can't rely heavily on a nasty curveball," Rockies Game 3 starter Josh Fogg said. "It's not going to be as nasty every time, and you've got to rely on some other pitches."
The Red Sox have to be more concerned about the impact of the switch to National League rules, which has forced Boston manager Terry Francona to remove offensive sparkplug Kevin Youkilis from the lineup to make room for erstwhile designated hitter David Ortiz at first base.
There you go. There are just enough intervening variables to prevent anyone from assuming that the outcome of this year's Fall Classic was all but determined in the first two games at Fenway Park.
The Red Sox probably will win, considering that the vast majority of teams that jump ahead 2-0 in a best-of-seven series go on to complete their mission, but the Rockies are not an easily quantifiable group. They did the almost impossible to get this far, winning 21 of 22 games to take the National League wild-card berth and eventually the pennant, so it would be unwise to dismiss them just because they came back a little stiff from that infamous eight-day layoff.
"We've done a lot of things that people haven't expected us to do all year," Rockies manager Clint Hurdle said.
The Red Sox, meanwhile, have pretty much been doing what everyone expected them to do, right up to Curt Schilling's gutsy start Thursday night and the amazing bullpen performance that followed. They'll certainly miss Youkilis, but that doesn't necessarily mean they'll be at a serious disadvantage with a player of that caliber at the front end of their bench.
People have been debating the impact of the alternating DH rule for as long as it has been used in the World Series. You can make the case that the American League team is seriously disadvantaged in the NL city because it is built around the DH and its pitchers get far fewer opportunities to swing the bat during the regular season.
The obvious counter argument holds that the NL team is disadvantaged in the AL city because it doesn't usually have a spare 100-RBI guy lying around to move into the DH role.
One thing is certain: The Red Sox will have quite a different look with rookie Jacoby Ellsbury hitting in the No. 2 hole and Matsuzaka batting ninth.
"We'll see how it plays out," Hurdle said. "Obviously, they built their ballclub for a DH. For 150-some games, they're going to have a big ham on the bat swinging it. They'll have to make an adjustment."
Francona has been kicking the situation around for several days and dodging questions about it at just about every World Series news conference until yesterday.
"What it really comes down to is the reality of it, two out of the three play, and it's really disappointing because we like when all three of them play," Francona said Wednesday. "They've all been mainstays in our lineup."
Listen to Peter Schmuck on WBAL (1090 AM) at noon on most Saturdays and Sundays.