Having lost out to Chelsea in the race to sign Basle winger Mohamed Salah - Liverpool were interested in the Egypt international but never made an official bid and were unwilling to pay what they considered an inflated asking price - there was more bad news with Johnson joining the injured ranks at the club's Melwood training ground.
With Daniel Agger (calf), Jose Enrique (knee) and Mohamed Sakho and Jon Flanagan (both hamstring) out in recent weeks Rodgers' options at the back are limited while defensive midfielder Lucas Leiva (knee) will be sidelined for up to two months.
Flanagan should be fit for Tuesday's Merseyside derby while Enrique is expected to be back in training next month and the manager is not looking for any last-minute additions to his defence.
Press Association Sport understands there are unlikely to be any arrivals in the remainder of the window despite Rodgers having just 15 players training this week because of illness.
"There have obviously been targets we've looked at but there's nothing imminent," said Rodgers on the prospect of new signings.
"We've looked at a number of players. I'll not give away any names, I'll never do that.
"We'll just see what the window brings for us. We're in the market for players to help the squad and if we can bring them in then great.
"We've got a lot of defenders and I'm not sure we need many more in - my first look will always be towards the young players.
"The likes of Jon Flanagan are coming back and hopefully one or two of the others might not be too far away.
"I wouldn't say we need any more defenders in."
A lack of fresh blood may damage Liverpool's bid for a Champions League place and Johnson's injury could not have come at a worse time.
"Glen has played a lot of the season having been injured and really put himself out for the team but unfortunately he's struggled a lot with a number of injuries," added the Reds boss.
"I just think it's now at that point where we need to get him right.
"The timeline he'll be out will be indefinite really. We'll just need to assess that and see how quickly he comes through that.
"He's had a real bad ankle for a period of time and just one or two other issues that haven't allowed him to be 100 per cent.
"I think everyone has seen over many years the speed, fluency and how good he's been, but for part of this season he's been restricted and that's obviously been difficult for him.
"We have one or two coming back but we've still got one or two that are out."
Rodgers is hopeful Lucas can recover ahead of schedule after sustaining medical ligament damage after coming on as a half-time substitute in last weekend's 2-2 home draw with Aston Villa.
But with an injury worry over fellow midfielder Joe Allen he looks like having to rely heavily on Steven Gerrard and Jordan Henderson with support from the likes of summer signing Luis Alberto, who has yet to get his Anfield career up and running.
"Personally I am disappointed for Lucas because he's been very important for our squad this season," he added.
"It was something that was innocuous really and has put him out for a few months.
"Hopefully he'll get back sooner rather than later.
"He'd been in good form this season and had worked his way back into the Brazil squad. Knowing what he is like, he'll be back sooner rather than later - and he'll do everything in his power to get back.
"In the meantime, that leaves us short of a really good player."