As reported by The Daily Mail, Celtic are said to have around £15m for a summer splurge on talent as they look to build a squad capable of success both domestically and in Europe.

Celtic's signing strategy has seen a shift since Brendan Rodgers arrived at the club, the Irish manager clearly favouring a more focused and tight squad of players compared to the scattergun approach of regimes previous.

That means he is unlikely to sign more than three or four players in the upcoming transfer window by our estimation. His current group of players have developed incredibly well over the last 12 months and only appear to be getting better.

Supplementing that group with some quality in key areas could take them to the next level.

Who should they target and in what positions?

Here are four potential Hoops stars we reckon could play a big role in the season ahead...

Ovidiu Popescu

23 year old midfielder Ovidiu Popescu has only been at Steaua Bucharest since last summer but has already racked up the appearances, making 30 so far in all competitions, with his club engaged in a title race in Liga I, the Romanian top-flight.

Also making 3 appearances in this season’s UEFA Europa League, it’s clear he’s seen as a key figure at the club. He’s certainly attracting plenty of praise.

Steaua owner George Becali, quoted by The Daily Record, said last month when the Hoops were linked:

"Ovidiu is the same type of player as Frank Lampard at Chelsea. He will be worth £25 million one day. He’s a central midfielder, who can also play right back – he’s so versatile. He runs at opponents and humiliates them when he gets past them. No one can keep up with him with that initial five yard burst of pace."

Having that kind of creative spark in midfield could be key and if his talent is truly as great as officials at his club say then making a move for the player could prove a bargain, even though the release clause in his contract is reported to stand at £8m.

Filip Manojlovic

Senior Celtic scout David Moss was reported by Serbian media to have travelled to Serbia specifically to watch giant goalkeeper Filip Manojlovic recently. Moss is a key figure at the Hoops and was instrumental in bringing Moussa Dembele to the club last summer. The fact he is scouting the stopper would suggest the Hoops are interested.

Celtic already have a quality goalkeeper in the form of Craig Gordon but given his age, it would make sense that if Brendan Rodgers was to bring in back-up, he would be young and ambitious and potentially be part of any transition between the sticks at Celtic Park.

6ft 5in tall and just 21 years of age, Manojlovic is already first choice at Red Star Belgrade and has even won a senior cap for his country after representing Serbia at four age levels.

He's one to watch for the future and if Celtic can invest in him early this summer, they could have a potential bargain on their hands.

Patrick Roberts

Keeping Patrick Roberts at Celtic is not going to be easy and it seems certain that, initially at least, he will return to Manchester City in the summer for pre-season training. His 18 month loan deal will have come to an end, bringing closure to a mutually beneficial relationship for both club and player.

He's been a sensation in attacking midfield for the Hoops and even if they have to shell out a significant sum to land him, it's something they should consider.

He has the ability to play in the UEFA Champions League and not only that, but improve year on year. He is only 20 years old after all.

Rodgers knows how to get the best out of him and if the deal can be done then it's worth a chunk of their £15m budget in the upcoming transfer window.

Liam Lindsay

An outstanding prospect in the centre of defence, Liam Lindsay is one of the few talents in Scotland outside of Celtic that may have the potential to star for the Hoops. Unlikely to be a first choice immediately, Lindsay would certainly provide good cover for the likes of Jozo Simunovic and Dedryck Boyata, especially so considering the likes of Efe Ambrose and Kolo Toure are unlikely to be playing for the Bhoys next season.

Lindsay is a player not just with the physical attributes to be a success in the Scottish Premiership but at Partick Thistle has learned how to play the ball out from the back which is a key attribute for any defender playing under Brendan Rodgers.

He's been a stand-out for Alan Archibald's men in the club's finest season for over 30 years and if Celtic don't move for him, it seems likely he is a 21 year old with a bright future at a bigger club ahead of him.