Rennes are open to cashing in on Camavinga, who has a year left on his contract, in the final week of the transfer window while Atletico Madrid have told Saul he can leave if they receive a suitable offer.
Both remain of interest to United -- who have prioritised midfield reinforcements over a right-back ahead of the Aug. 31 deadline -- but any move is set to depend on players leaving Old Trafford, something club bosses believe is increasingly unlikely as the window draws to a close.
The loan exits of Axel Tuanzebe, Andreas Pereira and Brandon Williams have earned minimal fees and while there is interest in members of Ole Gunnar Solskjaer's first team squad including Jesse Lingard and Eric Bailly, there are no concrete proposals on the table.
An enquiry made by West Ham for Lingard was knocked back last week. If Atletico were willing to entertain loan offers for Saul, including a loan fee and an obligation to buy in the future, it would give United more flexibility to negotiate an agreement.
Atletico also showed an interest in Lingard earlier in the summer. Chelsea are among a number of clubs who have been alerted to Saul's situation, although sources close to the 26-year-old have told ESPN that there are a number of obstacles in the way of any potential move to the Premier League.
United still expect Camavinga to move to Spain, or stay in France with Paris Saint-Germain, if he leaves before the deadline.
Sources at United have told ESPN that if PSG agree to let the forward, who has a year left on his contract, leave they could look to make an offer for Paul Pogba.
Pogba is yet to sign a contract extension at Old Trafford and if new terms are not agreed, he will be able to walk away for nothing next summer.