It's not just about what happens on the pitch.
What was reported/speculated on was that a huge part of the falling out between members in the squad this fall/early winter was over some established players not working as hard as some other players in training. Kaboul, Capoue and Adebayor were swiftly dropped as it seemed Pochettino seemingly sided with some of the younger players in the squad on this issue. Lennon was, like those 3, far from the squad and shipped out on loan at the first opportunity.
I don't know for sure what Lennon has and hasn't done in training over the last couple of years and in his Spurs career in general. I can't remember ever hearing claims about him being a particularly good trainer. Unlike what we've heard about Bale, Modric, Defoe and a handful others in the past and a very solid chunk of our current players like those mentioned above. I got the feeling that he was more content where he was and not someone to push himself hard every day type, a bit like GB is saying. But I obviously can't be sure. I think that explanation fits better with him leaving the club on loan in January with no one coming in to replace him.
I'm hoping we get a bit of a synergy effect from having a relatively large group of players who are true professionals looking to improve day in day out. It must surely be a huge inspiration for players like Pritchard coming back from loan, Alli coming in a new young signing and our current development squad players like Onomah to see young first team players be very hard working in training, push their way into the first team and continue to work hard. I really think that's the kind of effect that can spread in a group of players and a club and set a standard that others will be more likely to live up to. I think this is what Pochettino is trying to do.
If Lennon wants to be a part of that, is in fact ready to start working his socks off every day in training to improve, to be a role model for younger players and push himself to get better at this stage of his career I would certainly be delighted to see him back at the club. Regardless of what has happened before, and again - not claiming to know for sure what has happened before.