Brendan Rodgers has said that a challenge from Rangers' Andy Halliday on Patrick Roberts last week could have broken the Celtic wingers' leg.

Halliday was shown a yellow card in the fourth minute of the Scottish Cup semi-final for the tackle and Roberts went on to play over 80 minutes as Celtic ran out 2-0 winners. However, in a discussion about video technology Rodgers brought up the tackle and said ti should have resulted in a sending off.

"[Video technology] will be interesting," the Celtic manager said. "If you assess a lot of yellow cards I would be nearly positive that up to 50% of them would be reds.

"We've experienced that in this week. If there's video technology in our game at the weekend then they would have lost a player after three minutes.

"That's why I ask where the line's drawn. I haven't seen any of [the detail] yet but I think it's great."

Asked if Roberts was lucky to avoid injury, Rodgers said: "I think he was very, very lucky. I think thankfully for himself he saw it coming out of the corner of his eye.

"If he's planted then it's a broken leg.

"At that speed going in, that was reckless. Thankfully he came out of it unscathed. He was fine, went on and was brilliant in the game."

Rodgers was keen not to take the bite out of the derby but said that player safety was paramount. He also dismissed the suggestion that referees would be reluctant to send players off early in the game.

"It wasn't a good challenge at all and I think everyone saw that," he said. "I think everyone recognised it and I don't know whether Willie was unsighted but yeah, you're hoping those types of incidents are seen in the game because you want a Celtic-Rangers game to be highly competitive but you don't want your talented players being injured and that's important.

"If there's a bad tackle within ten seconds because someone can't control their emotion then whether it's ten seconds or 85 minutes doesn't matter. If it's a reckless challenge, dangerous challenge or violent conduct."

Speaking about the wider issue of video technology, which FIFA has suggested will be introduced in the next year, Rodgers welcomed the idea.

"Hopefully it can be used sensibly and that would be great for referees because there's big pressure on referees and any help that they can get would be good," he said. "It gets somebody else's perspective on it.

Accepting that decisions still came down to opinion, Rodgers also supported the current use of additional assistant referees. Having criticised match official Don Robertson for his performance in a previous game, he praised his contribution at Hampden.

He added: "I thought it worked well at the weekend there. We sat here last week and talked about the decisions from before in the game against Ross County.

"I thought Don did great between him and Willie [Collum] when they gave the penalty. It was a clear penalty but him being there probably rubber-stamped it for Willie. Don made a really good decision so that helped.

"If you've got video with that as well then that slows the decision down, which is important. Not too much but if it slows things down to assess the incident then you hopefully get the correct decision."