Dundee United manager Micky Mellon has defended the club's protocols ahead of the Covid-19 outbreak which has left assistant boss Stevie Frail in a "very poorly" condition.

Mellon emerged from a 14-day isolation on Friday after three members of staff tested positive – Frail, coach Dave Bowman, and a physio.

Nine players were also self-isolating and some will not get back in training until after Sunday's visit of Scottish Premiership leaders Rangers.

"Stevie Frail is very poorly and that's been a bit of a shake-up," Mellon said. "He's not going to be with us for a good few days anyway.

"He didn't have symptoms initially but tested positive and he gradually just got worse and worse and he is still getting worse.

"We are thinking about him and hopefully he recovers quickly.

"There's still a few players that will be away until Tuesday. Most of them are the injured ones, there's one or two that might have played."

United were criticised by Scotland's national clinical director, Jason Leitch, for staging a 49-man traditional squad photo just ahead of the outbreak but Mellon defended their actions.

"First of all I don't know where the Covid came from," he said. "In terms of regretting the picture, no, because we followed all the protocols absolutely.

"Everybody jumped on it quite quickly. If you followed the detail, that was our bubble, and there were two doctors in the picture, who had asked if we had followed the protocols.

"We were told the different things we had to do and followed that procedure. Teams had done it before us.

"We were there for, I think, about a minute and a half.

"We are all learning and if that's a lesson then everybody will learn from it. But we didn't go into that thinking 'let's give ourselves a right good chance of getting Covid'.

"I sympathise with Jason Leitch and his government because we are going through something for the first time. Lessons will be learned.

"I hope we never go through this again but I can assure you we'll be better at it the next time, including the government. That's for sure."

Mellon added: "For seven months we have not been touched by Covid. We followed all our protocols and we are very stringent here.

"And unfortunately one of the lads on the coaching staff didn't feel so good on the Saturday when he got tested and all of a sudden, because we were in contact with him, we had to stay home. But only Stephen Frail and Dave Bowman were positive, the rest of us were negative.

"In terms of where did we get the virus from, I had plenty of time at home, as you can imagine, 14 days, so I read a lot of stuff. And when I saw that a Trident nuclear submarine got a Covid outbreak, then I thought we've all got problems. It just shows how difficult it is to gauge where it's coming from."

Mellon had to watch from home as United lost 2-0 to Livingston last week and his attempts to feed instructions to academy coach Thomas Courts were undermined by a 30-second delay in the footage.

Mellon said: "My missus walks across the room and her phone beeps and 30 seconds later they score and I go 'aw, no' and she goes: 'What, not another one?' She was 30 seconds ahead of me and had got a text alert.

"It was difficult, I won't lie to you. Thirty seconds is a long time in a game of football. You phone to ask them to squeeze up a bit and they have just had a shot at goal."