Ben Roethlisberger has already built a Hall of Fame resume, with two Super Bowl titles, five Pro Bowls and a legacy unmatched in Pittsburgh since the days of Terry Bradshaw.

So you'd think he'd have nothing left to prove, right? Well, not so fast. There is one white whale that continues to haunt Big Ben.

Though the Pittsburgh Steelers and New England Patriots have made regular appearances in the postseason for well over a decade, the teams have not met in the playoffs for 12 years. It was also their lone postseason meeting in the Tom Brady-Ben Roethlisberger era, a matchup at Heinz Field back in 2005, in which New England won, 41-27.

In the regular season, the Roethlisberger-led Steelers have gone 3-5 against New England, and in the playoffs, that one loss. He's won in Foxboro on just one of four occasions, and that was in 2008, when Pittsburgh's offense and defense were both very different than they are today -- as were New England's since Brady wasn't even playing in that game due to a season-ending knee injury he suffered in Week 1. Comparing that game to Sunday's is as apples-to-oranges as it could be for two teams still in the same locations and bearing the same names.

But the level of pressure Roethlisberger and the Steelers are facing -- especially in light of Antonio Brown's not-wise decision to broadcast live from the team's locker room on Facebook -- cannot be swept aside. And this pressure is what will either make or break the Steelers' on-field performance on Sunday. The good news is that Roethlisberger has the strongest supporting cast he could hope for when heading into such a significant game.

There are, of course, the Killer B's: Beyond Ben, they include Brown, running back Le'Veon Bell and now, apparently, kicker Chris Boswell, whose six field goals against the Kansas City Chiefs not just set a postseason record, but also led to Pittsburgh's 18-16 win. There's also another B: The (arguably) Best all-around offensive line in the NFL's final four. 

Bell, in particular, has been having an historic postseason. He's the first player in league history to rush for 150 or more yards in each of his first two playoff games. And his masterful performance can be chalked up to both his talent and that of his offensive line. As Nathan Jahnke of Pro Football Focus noted after the divisional win over Kansas City, Bell's 81 yards before contact were also supplemented by 89 yards after it. Further, Roethlisberger has been sacked only two times in two playoff games, and a mere additional 17 in the regular season, a new personal low.

Another B: The Steelers possess the Best defense still in the playoffs, certainly an asset against a Patriots offense that will need to be slowed and controlled when it's on the field. Pittsburgh's defense is giving up touchdowns on only 47.54 percent of opponent red-zone appearances, or fifth in the league. But it also relies on Roethlisberger's offense to keep Brady away from action.

And there are red flags that could lead to Roethlisberger struggling on Sunday.

Of the Steelers' five losses in the 2016 regular season, three came on the road. Roethlisberger has thrown nine touchdowns to nine interceptions on the road this year, playoffs included, compared to 22 touchdowns and seven interceptions at home. If Roethlisberger makes mistakes and Belichick, true to form, takes away either Bell or Brown at any given moment, that subtracts two key elements of what makes Pittsburgh's offense work. And given the Steelers went 0-for-4 in red zone appearances against the Chiefs, Roethlisberger's helpers -- not just Bell, Brown and the line, but also tight end Jesse James and receivers Eli Rogers and Cobi Hamilton -- may still prove to not be enough.

Roethlisberger is also staring down a defeat of his own personal history. The Steelers' first Super Bowl win with him as the starter, in 2005 over the Seattle Seahawks, is widely believed to have happened in spite of him (Roethlisberger had a completion percentage of only 42.9, threw for 123 yards and had no scores and two interceptions). His struggles, including two turnovers, also led to Pittsburgh's loss to the Green Bay Packers in the Super Bowl six years ago. There is a prove-it moment at stake here, where Roethlisberger can show he's as invaluable to his offense as Brady is to New England's.

If there is any year where Roethlisberger seems set up for success and for the much-needed victory over the Patriots in Foxboro, it's Sunday's AFC Championship Game. His starters in Bell and Brown are healthy and performing at playoff-caliber levels. The offensive line is as good as an NFL team could hope for. And the defense has continued to improve throughout the season, then taking off like a rocket upon the Week 11 return of linebacker Bud Dupree, whose five sacks (including postseason) since then have changed the whole tenor of that side of the ball. 

But the Roethlisberger show stealing the spotlight on the biggest and most intimidating stage he's been on in over a decade would do much to solidify his standing among the top quarterbacks of his generation. There are many legacies on the line for the Steelers on Sunday -- Roethlisberger's is squarely among them.