The concerned Millers chief spoke about his lack of squad depth at the weekend - and said that the Millers were 'one or two injuries away from a catastrophe' after young striker Josh Kayode sustained a hamstring injury in the friendly draw at Mansfield Town.

So far, Warne has brought in six players in Peter Kioso, Cohen Bramall, Tom Eaves, Jamie McCart, Conor Washington and Cameron Humphreys.

But that is offset by the fact that some significant departures have been announced from last season's promotion-winning side, headlined by the exits of Michael Smith and Michael Ihiekwe to Sheffield Wednesday.

Loanees Rarmani Edmonds-Green, Jordy Osei-Tutu and Will Grigg also returned to their parent clubs.

Angus MacDonald - who has joined Swindon Town - Mickel Miller, who has signed for Plymouth Arygle and Joe Mattock - now at Harogate Town - were also freed, while wantaway striker Freddie Ladapo joined Ipswich Town early in the summer window.

It leaves United light in several areas, most notably up front.

Warne, speaking after his side's 'disappointing' friendly draw at Doncaster Rovers, said: "I think I have a centre-half joining us on Thursday.

"I thought I had another midfielder joining us, which has been going on for about four weeks, but then another Championship club have come and nicked him at the last minute, so that's hugely disappointing.

"We are obviously on a really active drive to get a striker and obviously need more oomph up top. That goes without saying.

"I still think we are a few players short. We need new bodies and men in the team and we need greater performances out of the players that we have currently got."

Warne has expressed his desire - in an ideal world - to bring in five more players before the start of the season to take his summer signings count into double figures, but he realistically feels that is probably pushing it somewhat given a largely 'frustrating' window thus far.

While bringing in six new players, the club have also missed out on number of targets and have been 'gazumped' on several occasions in Warne's words.

Warne, whose side kick off the new Championship season at home to Swansea City on Saturday week, added: "I will be amazed if we can get five in before the start of the season.

"We might get two or three in before the start. The window does not shut until September. I know where we are in the pecking order and we have to be patient.

"We try so hard to get signings. It's like a never-ending thing. Unfortunately, sometimes, we just get gazumped and that's the real reality.

"It's not just a financial gazumping, it's a club gazumping because some of the (other) clubs might be more attractive to other players.

"It feels like you are one or two signings away from improving the group, which then allows other players to come in as well. At the moment, it's just been a bit of a frustrating window and I feel like we have been close to some.

"I have said that before and in recent weeks. I don't want the Rotherham fans to think 'oh wow, he is saying that again', but it is the truth - I am not going to come out here and lie.

"But we feel close to one and I think that will definitely happen for Thursday. I believe All the paperwork has been done; all the paperwork was done for another, but that has been swept from underneath me. I am just hopeful we get more in before next weekend, but then it allows you very little time to work with the team. But it is a necessity."

Rotherham United transfer latest: Millers set to sign experienced defender on Thursday