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It seemed like everyone in Fenway felt it: uncertainty about the Red Sox's chances heading into the playoffs.

Boston shortstop Xander Bogaerts noticed. Between games during their American League Division Series, he turned on the television and couldn't help but feel a building anger and frustration: Insider after insider, analyst after analyst, talking head after talking head was choosing the Yankees to knock off the Sox. He turned off the TV and swore not to turn it on again.

"It was a tough off day," Bogaerts told the media, soaked in champagne in the Yankee Stadium clubhouse after Boston closed out New York on Tuesday. "I didn't watch a lot of TV after that."

Even the likely American League MVP seemed uneasy in the moments leading up to the Red Sox's opening series. As Game 1 batting practice ended at Fenway Park last Friday, Mookie Betts put his head down and headed straight toward the dugout. Nudged, he was asked how he was feeling.

"That's a really good question, man," Betts told Bleacher Report. He paused and sighed. "I don't know, man."

Now, as they head into the American League Championship Series against the Astros, beginning Saturday night at home, the doubts and concerns remain despite the four-game victory over the Yankees. The sportsbooks, per OddsShark, say defending World Series champion Houston is favored, not the team that led the majors in wins during the regular season.

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For all of the franchise's success in recent years, including the team-record 108 victories this year, many key Red Sox players are not playoff-tested. The only player on the active roster with World Series experience is Bogaerts. Ace Chris Sale, despite his decorated resume, has never played past a division series. Closer Craig Kimbrel was famously left in the Atlanta bullpen when the Braves had the opportunity to advance to the 2013 NLCS. And starting pitcher David Price's 5.28 ERA in 75 postseason innings speaks for itself.

"Everything you did before in the season doesn't matter anymore," said Red Sox slugger J.D. Martinez. "This is the playoffs. From here on out, everything starts at zero. Look at the scoreboard, all your numbers are zero, zero, zero. So you know what's at stake."

Betts is the best example that these Red Sox are in challenging new territory. The right fielder struggled through the ALDS, hitting .188/.316/.566 with three hits and two RBI. That's a long way from the .346/.438/.640 line that led him to the AL batting title this past season. And it continued his career trend in the postseason, where he's hit .238/.333/.667 in 42 games. The Sox will need more than three hits from their best player and leadoff hitter to have a shot at matching an Astros lineup featuring Carlos Correa, Alex Bregman and Jose Altuve.

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On the mound, the team survived the Yankees with the bullpen's best bend-but-don't-break effort. Like when Suicide Squad hit theaters, "Red Sox Playoff Bullpen" played out almost exactly as poorly everyone thought it would. In Game 1, Sale handed off a 5-2 lead after 5.1 innings, and Boston escaped with a 5-4 victory. In a Game 2 loss, Price melted down early and the bullpen allowed another three runs. As they closed out the series in Game 4, the Red Sox turned to Sale instead of a reliever for the eighth inning before handing off a 4-1 lead to Kimbrel for the ninth. He loaded the bases and allowed a warning-track shot that with a few more feet would have won the game for New York—the Sox prevailed 4-3. The whole ordeal was like watching Han, Luke and Leia trapped in the trash compactor, every next thing pointing towards an epic disaster before some miracle pulls them out of trouble.

It could be a relative unknown who can be the rock Boston will need in the tightest moments against Houston.

Ryan Brasier started this season in Triple-A Pawtucket after spending last year in Japan. With the fans in Yankee Stadium itching and scratching, looking for any bit of hope to erupt into pandemonium, Brasier shut down the Yankees in the seventh of Game 4. He finished the series with four strikeouts in 2.1 innings, allowing no runs and earning the trust of manager Alex Cora in high-leverage situations. He'd spent nearly five seasons toiling around baseball before finding himself in the middle of a high-tension playoff series, once cursing at Gary Sanchez, telling the Yankees catcher to get back in the box before blowing him away on a 97-mph fastball.

Cora will need Brasier and the bullpen in the ALCS, another change from Boston's regular-season reality.

"We work differently than other teams," Cora said during a press conference ahead of Game 1 of the ALDS. "We relied on our starters throughout the season. They carry us. We felt that on a nightly basis they were going to give us a chance to win—either five innings, six innings, whatever. They were very consistent about it."

Sale, Nathan Eovaldi in Game 2 and Rick Porcello in Game 4 gave Cora effective starts in the ALDS. But he'll want more from Price than the 1.2 innings he got in Game 2. In many ways, the Red Sox's chances hinge on Price finding form. Cora is committed to the 33-year-old left-hander sticking in the rotation, telling WEEI.com that he believes his star pitcher only needed to make some mechanical adjustments.

"There were a few things I noticed that he's gotten away from [his] last few starts," Cora said. "Hopefully he can make that adjustment. ... I do feel that with that adjustment, he'll be back to being the guy who pitched in the middle of the summer, and he'll dominate again."

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Cora himself is in his first postseason as an MLB manager and did not excel as a playoff player—he hit .154 over 26 at-bats in six series. But he was the shining light for Boston against the Yankees, seemingly unable to make a bad decision. The Red Sox have seen the Astros before, but nobody knows them better than Cora, who was Houston's bench coach during their World Series run last season.

Following multiple seasons when many felt former skipper John Farrell was not aggressive enough in his managerial style, Cora has flipped the script. His decision to sub in Brock Holt and Rafael Devers for Ian Kinsler and Eduardo Nunez in Game 3 of the ALDS paid dividends, as did having Sale come in to set up Kimbrel in Game 4.

"I'm trying to remember some things that I told [Cora] that I wish I wouldn't have," Houston manager AJ Hinch said to the media Wednesday before his team's first workout.

"He was obviously right next to me every step of the way. As a bench coach, you're kind of involved in everything, but maybe master of nothing when it comes to being in charge."

Houston is the favorite to win the series, topping Boston on paper in the bullpen and the rotation while featuring a comparable lineup. Several things will need to break the Sox's way in order for them to move onto the World Series. And if the Red Sox didn't like what pundits were saying before the Yankees, they won't like what they hear as they prepare to face Houston. But the rematch of last year's ALDS is set, and this time, the stakes are higher.

"We're ready for another shot," Porcello said.