It seems ludicrous now but two years ago at this time, there were serious questions about whether the Pittsburgh Steelers had a legitimate No. 1 wide receiver on their roster.

Mike Wallace had signed a five-year, $60 million contract with the Miami Dolphins a month earlier, taking his blinding speed and big-play ability to South Beach.

That left the Steelers with a pair of sub 6-foot wideouts -- one of whom had been plagued by injuries in his first three seasons and the other who had three 100-yard games and seven touchdown receptions in his first 38 NFL games.

Both Emmanuel Sanders and Antonio Brown, third- and sixth-round draft picks respectively in 2010, made the Pro Bowl in 2014.

Sanders elevated his game to new heights in the Mile High City, catching 101 passes for 1,404 yards and nine touchdowns after signing with the Denver Broncos.

His good friend eclipsed that production as Brown caught 129 passes for 1,698 yards -- both led the NFL -- and 13 touchdowns.

Brown has not redefined the position after following a breakout season in 2013 with one for the ages. But the 195th pick of the 2010 draft should, with his enormous success over the last two seasons, spark discussion of what exactly constitutes a No. 1 wide receiver.

Or at least make the definition more elastic.

Brown is not the prototypical No. 1 wide receiver in that he is listed at only 5-10, 186 pounds and plays a position where there seems to be a fixation on height.

But there is a reason why Steelers safety Mike Mitchell said last season that Brown plays as if he is at least a foot taller.

Brown led the NFL with 85 first downs last season. Brown’s 129 receptions in 2014 were the second-most in NFL history, and he caught 70.9 of passes thrown his way.

That ranked ahead of wide receivers such as Dallas’ Dez Bryant (63.8 percent), Denver’s Demaryius Thomas (60.3), Chicago’s Alshon Jeffrey (58.6) and Detroit’s Calvin Johnson (55.5).

All of those wideouts are listed at 6-2 or taller.

So try telling Brown, a first-team All-Pro selection in 2014, that taller wideouts are a quarterback’s best friend.

Brown, who only turns 27 in July, had at least 90 receiving yards in 14 of the Steelers’ 17 games last season, a strong indication that opposing teams were unable scheme him out of Pittsburgh’s offense.

And the Steelers are confident Brown will ascend -- or at least continue to produce at a high level -- because of his most enduring attribute.

“He is addicted to work and preparation, and it serves him well in the line of work that he is in,” Steelers coach Mike Tomlin said. “This guy is the last guy off the field every day. He brings a ridiculous work ethic to the table. The guys respect him for what he is capable of on the field, but they probably respect him more for what he is willing to do on and off the field in regards to his preparation and play. I would probably describe Antonio as OCD, clinically.”

And, yes, that is a compliment.

The ultimate one actually.

“The (great) ones that I’ve been around, it’s what you don’t see,” Tomlin said. “Yes, they have special capabilities, but you know there are a lot of guys in our game at this level that have special capabilities. The great ones that sustain it for any length of time they are smart, they are driven, they are hard working.“