Michael Appleton's switch from Blackpool to Lancashire rivals Rovers was finally confirmed just two hours prior to kick-off, meaning he was not in attendance in the Black Country and instead watched the televised fixture.
Gary Bowyer, with three wins from his three previous games at the helm, remarkably looked set to hand over the reins boasting a 100 per cent record after Jordan Rhodes' contentious first-half penalty - his 14th goal in Rovers colours - handed the visitors the lead.
But Johnson nodded home in the 74th minute to level matters and ensure both sides rightfully finished with a point apiece.
Rhodes should have tested Carl Ikeme when sent clear into a promising position and it was Rovers goalkeeper Jake Kean who made the first real save of the game after 19 minutes, parrying well from Kevin Foley's flicked effort.
But then Wolves made a mess of things defensively and gave away a cheap free-kick 20 yards out in a wide position, which was played short to Ruben Rochina.
He danced into the area before receiving minimal contact from Bakary Sako and the Spaniard made the most of it, with referee Dean Whitestone initially failing to award the penalty before his assistant flagged, leaving Rhodes to do the rest from the spot.
The goal seemed to knock the stuffing out of Wolves although they continued to probe.
Rochina again brought a save out of Ikeme at the start of the second half.
Wolves searched for an equaliser and Saunders introduced Jamie O'Hara in the 73rd minute and the midfielder made an instant impact, swinging the ball in from the left with his first touch for Johnson to nod home an equaliser.
And despite plenty of Wanderers pressure that was the way it remained, with both sides likely to be happy with a point.