I guess it depends on how they view Pedro and probably to a lesser extent Sanchez. Those two with Neymar added give them variety up top, where as before Fabregas would get a fair few games up there. Neymar can take over for Messi when they want to rest him as well. Not sure how much they rate Tello as well.
Deeper there's still room for Fabregas but right now that trio of busquets, xavi and iniesta still has about 2 seasons to go. I'm not too clued up what other young players they have but whilst Fabregas would still get a lot of games he's probably gonna have to wait a few seasons to really become an important player and that's even if they think he can take Xavi's role, if he's seen more as an a/m than with iniesta it could be a fair while.
Plus I don't know what their cash levels are like but could be they need cash to stengthen the defence which you'd think they'd do. Could be a situation where they don't particularly want to sell but they might just might need to, to improve the team now, and then they'll think on Xavi's replacement over the next two seasons or so if they don't have someone already in mind. Plus maybe Fabregas himself would like to be a fixture of a team rather than someone who is just slotting in.