On Monday the match review panel cleared North Melbourne forward Thomas, 25, for the bump on Reid that left the Pies' backman with blood pouring from his mouth and concussion.
The AFL today confirmed it would not challenge the Match Review Panel's decision to take no action against Thomas for his bump on Reid.
The Kangaroos goalsneak said he had "most definitely" been worried about a potential sanction before the panel handed down its ruling.
"It was one of those unfortunate things I guess," Thomas told NMFC.com.au on Tuesday. "It was just an accident.
"We collided heads and it was just one of those unfortunate things. We both hit heads, we both went down.
"Unfortunately for him, he didn’t come back on. He was knocked out, I come off with a pretty sore cheek and I’m just happy that he’s alright.
"I didn't really think about it too much after the game. I thought there wasn't really much in it, but after looking at it yesterday I did think I was in a bit of strife.
"I'm just happy I don't have to miss any games of footy. Obviously I missed five games last year through suspension, so I'm just really happy that I get to run out with my teammates this week and put on that guernsey."
An ugly war of words broke out between North Melbourne coach Brad Scott and Collingwood counterpart Nathan Buckley at their respective press conferences after the game.
Buckley said the hit was "pretty average" and "unprovoked", and while he said he didn't want to pre-empt the MRP's judgement "clearly if it is behind play and it is high you're in a bit of strife".
Scott responded by saying Buckley should "keep his opinions to himself when it comes to things that will be taken care of by the powers that be".
On Monday, Buckley told Triple M radio that with hindsight he wouldn't have made the comments he did, but he still thought Thomas had "got away with one" by avoiding suspension.
Thomas said the hit was accidental and was a shepherd that ended up in a head clash.
"If our heads didn't collide we probably wouldn't have heard too much about the whole situation," he said.
"Our heads did collide and he did get knocked out.
"It's in the rules if you do bump and someone gets hurt, it's going to get looked at.
"Unfortunately for him and for myself as well, we did collide heads and I was a bit dazed and so was he.
"It was one of those unfortunate things. I saw Lachie Hansen running onto the footy and I was kind of running towards him and probably the last split decision was to shepherd Ben Reid.
"It was unfortunate we collided heads … we both hit heads and both went down."
Thomas said he ended up with "a pretty sore cheek", but he was now keen to move on from the incident.
"It was just an accident and in terms of the heat of the moment, it got a bit heated towards the end but that's footy," he said.
"After the game we all shook hands and got on with it.
"I hope he was all right, and by all reports he is, so just moving on with it now … it's a big game for the club this week and [I'm] just focusing on Geelong."
Lindsay Thomas is a forward in NAB AFL Fantasy. He averaged 68.56 points in 2012. Register your team at our AFL Fantasy Hub
Jennifer Phelan is a reporter for AFL Media. Follow her on Twitter @AFL_JenPhelan