Button is out-of-contract at the end of the season while it is understood McLaren has an option to extend Magnussen's contract.
Ahead of this weekend's season ending Abu Dhabi Grand Prix, the team has issued a statement confirming that any driver announcements for next season will not be revealed until December 1 at the earliest.
“Selecting the optimal driver line-up for a Formula 1 team is clearly an important process, and it is therefore one that requires precise and prolonged analysis,” read the statement.
“That being the case, and in order to avoid distracting the race team from its primary objective during the final grand prix weekend of the season, which is to secure the best possible on-track results, we have decided to defer our final deliberations relating to our 2015 driver line-up until a date no earlier than Monday December 1.”
The team are also expected to run a similar iteration of its Honda powered MP4-29H car at the Abu Dhabi test following Sunday's race. The car made its debut during a filming day run at Silverstone last weekend.