The 20-year-old, who only appeared as a second-half substitute in the Perth encounter, was forced off late on to leave Celtic with only ten men.
It followed the attacker assuring the Celtic bench he was fine to play on when Lennon was in the process of making a final substitution minutes earlier.
This chain of events caused a stir on social media, with the Celtic manager appearing to tell Johnston to “f*** off” as he made his way towards the tunnel after being forced off – an interaction Lennon yesterday sought to present as having been misconstrued.
“I basically just said to him go in because it was freezing and there’s no point him sitting there with his kit on having just come off with a bad injury,” he said. “‘Make sure you go inside and keep warm’. Too much has been made of that.”
Lennon’s greater concern was the knee twist that will cost him Johnston across a hectic period of fixtures and which represents a further setback to a player who has not had his troubles to seek with injuries, a groin strain suffered in September sidelining him for almost two months.
“Mikey got a bad one [on Wednesday],” he said. “We are just waiting to see, but it’s going to be long term. A couple of months at least. It looks like there’s ligament damage there. We were trying to coax him in sporadically, give him 20 minutes here and there because he’s a real asset as an impact player so it’s a bad one.”
Lennon said there was “possibly” an element of inexperience in the player believing he could run the problem off. “There was movement in the knee,” said the Celtic manager.
“We were making a substitution at the time and I was ‘hold on a minute let’s see how he is’ and he said to Tim he was fine and he obviously wasn’t. So maybe there was a little bit of inexperience there but I’m not sure if that would have made the issue worse but it was quite clear he couldn’t continue after a few minutes.”
Although he has Mohamed Elyounoussi returning to training this week, and James Forrest and Jonny Hayes as other viable options – as Marian Shved does not seem considered to be – Lennon said it might cause his interest to pique as the transfer window closes.
“It might do,” he said of the potential for Johnston to change his thinking on any late approaches for additions. “[But] if we don’t bring anyone else in I’m delighted with the squad and with 3-5-2 anyway you are limited to the amount of wingers you can use.
“I’m not saying that’s going to be the tried and trusted formula for us going forward, but we’re playing very well with that formation. If someone is available we will maybe possibly look at it but at the minute there’s nothing on the horizon.”
Meanwhile, Lennon, inset, believes the 27-minute, three-goal blitz in Perth the other night set his team up for one of their best displays of the season – a perfectly timed showing as they look to maintain their five-point Premiership advantage in the away assignments against Hamilton Accies, on Sunday, and Motherwell, next Wednesday.
“It’s the best we’ve played for a long time. It was a test, we had a good attitude and we scored three great goals. Obviously you look for more of the same but every game is different with the way teams set up against you, and there’s a plastic pitch on Sunday as well so [a repeat is] not guaranteed.
“But we played very well, it’s as good a performance as we’ve had for a while.”