The Tricky Trees assured themselves of Premier League survival last term with Henderson and Keylor Navas - who has since returned to parent club Paris Saint-Germain - in between the sticks.
Despite struggling with an injury towards the back-end of last season, Henderson and Forest are both believed to be keen on a permanent deal for the Manchester United man, but there is yet to be a breakthrough in negotiations.
Should Forest miss out on the signing of the Englishman, journalist Fabrizio Romano claims that Arsenal number two Turner could instead arrive at the City Ground, where he would become Steve Cooper's first-choice shot-stopper.
The USA international only arrived at Arsenal last summer and has a contract until 2025, but he could be demoted to third choice at the Emirates if the Gunners sign Brentford's David Raya to compete with Aaron Ramsdale.
Turner failed to make a single Premier League appearance for Mikel Arteta's side last season, but he amassed four clean sheets from seven matches across the Europa League and FA Cup.
Meanwhile, the Iliman Ndiaye saga appears to be reaching its end, as Marseille have supposedly agreed a deal to sign the Sheffield United attacker this summer.
The 23-year-old has long been linked with a move to the Orange Velodrome, but the two clubs have failed to find common ground despite a protracted period of negotiations.
However, Romano now reports that Marseille have finally had a bid accepted by Sheffield United, and Ndiaye has already agreed a five-year deal with Les Olympiens until 2028.
The Senegal international supposedly touched down in Marseille on Sunday in order to undergo his medical tests, as he prepares to return to the club whom he represented as a youth player between 2010 and 2014.
Ndiaye subsequently had stints with Boreham Wood and Hyde United before arriving at Bramall Lane in 2019, and he has amassed 22 goals and 14 assists in 88 games since making his first-team breakthrough.
Ndiaye shone in the 2022-23 campaign with 15 goals and 12 assists from 52 matches in all tournaments, while he was also included in the Senegal squad for the 2022 World Cup, playing three games in Qatar.
Back in the English capital, Crystal Palace are reportedly hoping to ward off interest in highly-rated winger Michael Olise by handing the Frenchman a lucrative £100k-a-week contract.
Olise is thought to have attracted glances from Chelsea, Manchester City and Arsenal after registering two goals and 11 assists from 37 Premier League games for the Eagles last season.
However, Palace are under no pressure to sell the 21-year-old, who still has another three years left to run on the contract he signed upon his arrival from Reading in 2021, but those terms apparently include a £35m release clause.
According to Football Insider, Palace are ready to bump up Olise's wages from £45,000 to £100,000 a week in a bid to convince him to stay put at Selhurst Park, and they are confident that they will be able to retain his services for another year.
The report adds that Olise remains happy at Palace and is prepared to continue working under Roy Hodgson, who will be able to guarantee him weekly starts in the Premier League.
Olise previously turned out for the Man City and Chelsea academy teams before a five-year spell with Reading, who sold him to Palace for £8m in 2021, and the France Under-21 international has since amassed six goals and 19 assists in 71 games for the Eagles.
Finally, Paris Saint-Germain have allegedly rebuffed advances from Saudi Arabian outfit Al-Nassr for their captain Marquinhos, who is also determined to stay put in the French capital.
The 29-year-old has been regarded as one of Europe's leading centre-backs during his 10-year spell at PSG, who handed him the captain's armband in 2020 after Thiago Silva's exit.
Marquinhos only signed a PSG contract extension back in May, and those terms do not expire until 2028, but Al-Nassr and two other unnamed Middle Eastern sides have apparently tried to test Les Parisiens' resolve in the current window.
Marquinhos will be facing greater competition for starts next term following the signings of Milan Skriniar and Lucas Hernandez, but RMC Sport claims that the Ligue 1 champions have no interest in selling their skipper.
However, PSG could sanction a Saudi Pro League transfer for another one of their long-serving stars, as Marco Verratti has reportedly given the green light to a move to Al-Hilal.
Marquinhos has scored 38 goals and set up 10 more in 407 matches for PSG since arriving from Roma in 2013, winning the Ligue 1 title in eight of his 10 seasons at the Parc des Princes.