Former Toffees defender feels that the Scottish manager may have achieved all he can at Goodison Park and may need to move on this summer in order to fulfil his ambitions.Everton coach Alan Stubbs fears that the club\'s lack of success may force manager David Moyes to seek a new challenge.The former Toffees defender, who is currently coaching the reserves and Under-18s at Goodison Park, believes that the Merseyside side face losing their boss of 10 years unless they gain fresh investment.“The club has some big decisions to make,” he told The Daily Star.“Unless we get a new investor it is going to be very difficult for the manager. I think David has come to a crossroads in his career.“Does he stay at Everton, a club he loves and where he has a fantastic relationship with the chairman, or does he take that next step?”Moyes has long been touted as a possible successor to Sir Alex Ferguson at Manchester United and most recently suggested as a replacement for Harry Redknapp, if the Tottenham boss is selected to take up the vacant England job.And Stubbs worries that an opportunity at White Hart Lane could be too good for Moyes to turn down.“If he doesn’t go then [if Spurs came calling], it’s like everything in life, in that he might come to regret it,\" he noted.\"Sometimes, as with players, you don’t get a second chance.”