The ACT Brumbies No.2 was stretchered from Suncorp Stadium on Saturday night with a fractured and dislocated ankle after he was felled by Queensland Reds halfback Tate McDermott in a tackle.
McDermott made contact with the larger-bodied Lonergan from the side before his legs left the ground and became entangled, sending the Brumbies star to the turf.
Referred to as a hip-drop tackle, the action now attracts harsh punishment in the NRL and has recently been outlawed in the NFL.
Former Wallabies star-turned Brumbies coach Larkham said he hadn't seen many instances of it in his code of choice, but that he did take issue with McDermott's effort on Saturday.
"Yeah. I think it's legal; you get your arms on first, then you're allowed to trip," he said after his side's 20-19 defeat of the Reds in Brisbane.
"It's just nasty, isn't it? There's nothing illegal about it but obviously it's caused a significant injury and needs to be looked into."
Star Hurricanes and All Blacks halfback Cam Roigard also suffered a knee injury in a tackle during Saturday's earlier game.
Former Reds and Wallabies star Quade Cooper was watching from Japan and posted on social media that was "one reason the hip drop needs to be outlawed".
Cooper had presciently posted three days earlier that the hip-drop tackle should be outlawed in rugby, saying "there's a lot of focus of tackle height, but this in particular would be welcome by most".
2 crazy injuries in the last two games! Thoughts and prayers for speedy recoveries. That's one reason the hip drop needs to be outlawed. Clearly wasn't on purpose but it's such a dangerous position when beaten holding on from behind— Quade Cooper (@QuadeCooper) March 30, 2024
Larkham said the club wouldn't cite the incident but doesn't want the technique seeping into the code.
"I'd have to look at it again ... but if there's a trend going there and it's causing significant injury you have to look at it," he said.
"But I haven't seen it this year in rugby and I don't know whether Tate does it on a regular basis."
Lonergan's brother and Brumbies halfback Ryan captained the side and admitted he was shaken at halftime after the incident.
"I found it pretty tough at halftime, to be honest, it was first time I could reflect on it," he said.
"After that it goes back to doing your job. I'll go see him (at hospital) and see how he's doing. I'm sure he'll get on with it."
The Brumbies' victory moved them to 5-1 while the Reds (3-3) will enter the bye with back-to-back defeats.
