CELTIC have three prospective signings in the building and could have more on their way.

Wolves goalkeeper Sam Johnstone, Parma midfielder Oliver Sorensen and 19-year-old PSV Eindhoven midfielder Joel van den Berg were all at Celtic’s Lennoxtown training ground on Tuesday.

Martin O’Neill’s side have also been linked with Torino midfielder Gvidas Gineitis and a loan move for 18-year-old Chelsea forward Shim Mheuka.

The Scottish champions are also prioritising a left-back with the injured Kieran Tierney currently being covered by central defender Liam Scales.

William Hill Premiership clubs have until Thursday at 5pm to complete signings but Celtic have targeted the Europa League deadline of 11pm on Wednesday to finalise their squad.

When asked about numbers, assistant manager Shaun Maloney said: “When you’re looking at the really key ones within the squad, you’re looking at three to four.

“But then there might be some others. The club might decide to do business for the future as well.”

Johnstone has played more than 350 league games with the likes of Aston Villa, West Brom and Crystal Palace and the 33-year-old is set to provide competition for Viljami Sinisalo.

Maloney said: “Vil’s been fantastic for us this season. Whichever goalkeeper comes in, you have to say, it’s up to you. You go and try and push for that position.

“And it’s the same for Vil. You have to keep performing at the levels you are to keep the shirt.”

Celtic will be without Tierney and Kasper Hogh for Wednesday’s visit of Aberdeen as they both nurse thigh injuries, while striker Callum Osmand is set to be missing until after the international break with an ankle injury.

Maloney said: “In terms of any signing in that striker area, that will either transpire in the next 24-48 hours or we’ll just go as we are.”

A new left-back is a must though after Celtic decided against re-signing loan player Marcelo Saracchi.

Maloney said: “That’s a position that we’ve really needed to fill. And with the right type. I think ’Celo was that.

“Kieran started the season really well. But we need that back-up.”

Celtic are not looking for a central defender and there are no firm plans to sign a right-back despite Alistair Johnston being ruled out until October.

“It’s possible if the right profile comes, but we’ve got Colby [Donovan], we’ve got [Anthony] Ralston as well. We can definitely count on those two,” Maloney said.

“If Martin decides that’s the position he wants, then fine. But it’s not as urgent as the left-back position.”

Maloney talked about replacing the power and strength of Arne Engels in midfield following the Belgian’s move to West Ham, while Reo Hatate is likely to follow Paulo Bernardo out of Celtic Park.

Reinforcements in midfield could also ease the burden on Callum McGregor, who will return from illness to face Aberdeen.

“Alex (Oxlade-Chamberlain) has helped with that,” Maloney said. “After a lot of extra sessions, Alex was probably the best we’d seen him in the last game. So that definitely takes the burden off Callum.

“But Callum’s mentality is he wants to play every game. If we can get the squad right in the next few days, it might allow us at times to rest, not just Callum, but other players.”