Pope was forced off in the closing stages of Newcastle's 1-0 victory over Man United in the Premier League on Saturday night after dislocating his left shoulder when landing awkwardly.
The 31-year-old is due to see a specialist on Monday to determine the severity of his injury, and it is understood that the goalkeeper will be sidelined for between four and five months and may require surgery.
Pope's injury comes as a "massive blow" to Newcastle manager Eddie Howe, who had to cope without as many as 10 senior players for the win over Man United due to a severe injury crisis at the club.
Newcastle's No.22 is the latest name who will join Jacob Murphy (shoulder), Sven Botman (knee), Joe Willock (Achilles), Callum Wilson, Matt Target (both hamstring), Dan Burn, Elliot Anderson (both back), Sean Longstaff (ankle), Harvey Barnes (foot) and Javi Manquillo (groin) in a packed treatment room.
The absence of Pope will likely see Martin Dubravka step up and start between the sticks for the Magpies, while Loris Karius and Mark Gillespie are two other backup options at Howe's disposal.
However, according to the Daily Mail, Newcastle are exploring the possibility of signing free agent De Gea, who is one potential option under consideration by the club.
De Gea has been without a club since leaving Man United in July upon the expiration of his contract after 12 years at Old Trafford.
The 33-year-old kept a total of 190 clean sheets in 545 appearances for the Red Devils across all competitions and won five major trophies including the Premier League, FA Cup, EFL Cup and Europa League.
De Gea was also named in the PFA Team of the Year on five occasions during his time on the red side of Manchester, and he won the Premier League Golden Glove twice, claiming last season's award with 17 clean sheets.
However, Man United decided against renewing De Gea's reported £375,000-a-week contract and instead spent around £47m on Andre Onana, who has endured a difficult start to life at Old Trafford.
De Gea has been linked with a number of clubs since his departure from Man United, including La Liga outfit Real Betis and teams in Saudi Arabia, but a move at this stage has failed to materialise.
It is thought that De Gea's immediate availability and the fact that he would not command a transfer fee appeals to Newcastle, as well as his pedigree within the game.
However, the Spaniard would most likely be required to accept a lower salary compared to what he earned at Man United if he agrees to join Newcastle, in order to comply with the Magpies' current wage structure.
Newcastle currently sit sixth in the Premier League table, three points behind the top four, and will face Everton at Goodison Park in their next match on Thursday.