But the quarterback who will play opposite Brady on Sunday said the two-time MVP still is the standard when it comes to NFL quarterbacks.
"That's no disrespect to some of these other guys that are doing some amazing things in the NFL right now. But to me, it's about wins and championships -- and he's got more championships than anybody."
Brady is on pace to set career lows in touchdowns, passer rating and completion percentage, among other statistical categories, this season. But the 14-year veteran has led the Patriots to a 6-2 record despite directing an overhauled offense for much of the season.
Star tight end Rob Gronkowski missed the Patriots' first six games because of forearm and back injuries.
"For the first how many weeks of the season he was playing with receivers that nobody had ever really heard of, so you've got to give him credit for getting his team to 6-2," Roethlisberger said. "He's got great vision, he's got big arm strength, a great understanding of offense and defense.
"He finds ways to win. Fourth-quarter drives, Super Bowls -- and to me the No. 1 factor is championships."
Brady is 6-2 lifetime against the Steelers, and the eight-time Pro Bowler torched them the last time he played against Pittsburgh at Gillette Stadium.
Brady threw for 399 yards and four touchdowns in a 34-13 win in 2007, and his big game came after then-Steelers safety Anthony Smith had infamously guaranteed a victory over the undefeated Patriots.
Brady has completed just 55.7 percent of his passes while throwing nine touchdowns and six interceptions this season. His passer rating (74.9) is more than 20 points below his career average.
But Brady orchestrated a late touchdown drive a couple of weeks ago to hand the New Orleans Saints their only loss of the season.
Last Sunday, Brady rallied the Patriots from a 14-point halftime deficit in a 27-17 win over the Miami Dolphins.
"I think they're really finding their rhythm in the last few weeks," Steelers coach Mike Tomlin said of the Patriots' offense. "Getting back Gronk is a part of that.
"One of the things that's challenging about these guys is you better be prepared to defend a variety of personnel groups as they change the pace of the game."