It has all come down to Game 7 on Tuesday night for the St. Louis Blues and Dallas Stars in the Western Conference semifinals. We debate the key factors that will determine the outcome and make our picks.

Who or what will be the X factor for Game 7 of Stars-Blues, and who ya got?

Greg Wyshynski, senior NHL writer: I'm taking Dallas. I don't want to. I picked the Blues in this series and to emerge from the West, and my postseason prognostications have been so putrid that I really don't need any more red on my ledger. But Ben Bishop is the X factor:

• Bishop is on the road, where he has been great: a .931 save percentage in the regular season, and having given up two or fewer goals in four of six playoff road games.

• Bishop is playing after a loss; he's 3-1 in the postseason following a loss, with a .937 save percentage.

• Bishop is playing in a Game 7, where he's 2-0 with two shutouts.

And couldn't you see the ultimate story here being the collarbone incident in Game 6 followed by a Game 7 win? Plus, the Blues have been weirdly ordinary at home in the playoffs: 2-4, including two losses to Dallas in this series. So I would like to be wrong here, as the Blues are my pick. But it's hard to ignore what the Stars have going for them in Game 7.

Emily Kaplan, national NHL reporter: I'm picking the St. Louis Blues. The X factor that's going to make or break them? Special teams, an area where the Stars have had a clear edge so far. Dallas has been short-handed 20 times in this series for a total of 33:45 -- most of any second-round team -- and has killed off 90 percent of penalties. The Blues looked like they were making some power-play adjustments in Game 6. Despite going 0-for-5, I think they can break through in Game 7. Just as important is stopping the Stars' power play, which has gone 4-for-14 (28.6 percent, also best among second-round teams). Show proficiency in either one of those areas, and I see St. Louis prevailing.

Chris Peters, NHL draft and prospects writer: Seeing as I'm 0-for-the playoffs in predictions, I apologize to Blues fans for picking them in this Game 7. The X factor is Ryan O'Reilly, who has really not seemed to be himself in these playoffs. The big forward was a big reason the team made it to the postseason at all, given his career-high 77 points and solid all-around play since being traded to St. Louis last summer. In this series, O'Reilly has looked mostly fine for stretches, but one wonders if the adrenaline of a Game 7 could cure what ails him, if he is indeed playing through something. With the Blues able to play the matchups a bit more to their favor on home ice in Game 7, the stars are aligning to set up O'Reilly for a big breakout after posting five assists in the series so far.

Dimitri Filipovic, hockey analytics writer: I picked the Stars to win in seven before the series, so I have to stick with that at this point. It's a bit of a cop-out to say that the goaltending will be the deciding factor of a hockey game, but in this particular case it really is warranted because Ben Bishop's play has been the ultimate barometer for the Stars' chances of winning. In the three games they've won in this series, he has stopped 97 of the 102 shots he has faced (.951 save percentage). In the three games they've lost, he has stopped just 63 of the 74 shots the Blues have thrown at him (.851 save percentage). He has been nothing short of outstanding all season for them, fully earning his nomination as a Vezina Trophy finalist. Dallas will go as far as he'll take them, and assuming he's good to go following his injury scare in Game 6, the Stars will need at least one more gem from him in what will surely be a tense, tightly contested elimination game with little margin for error.

Ben Arledge, associate NHL editor: I originally took the Blues in seven, and they are coming off a big win facing elimination. And they are probably the better team on paper. And they are at home. There isn't a whole lot of reasoning for a change at this point, so let's ride with St. Louis. There are two big X factors here. First, Bishop's shoulder. He caught a Colton Parayko rocket off his collarbone in Game 6 and didn't finish the contest. The mere fact that he left the game worries me a bit, as it seems to suggest something more serious than a stinger, but it's equally likely the club was just playing it safe given the three-goal deficit. And while Anton Khudobin has been terrific this season in his own right, the Stars need Bishop at 100 percent to win, for the reasons outlined by Dimitri above. Second, I'd keep an eye on Mats Zuccarello. Despite skating somewhere between two to four minutes less per game than the other offensive catalysts on the Dallas side, the diminutive Norwegian has seven assists in the series. If Dallas is going to win this, he's going play a part, even if it's behind the scenes. He has plenty of playoff experience from his days with the New York Rangers, and knows what it takes to win a Game 7.