Manchester City manager Mark Hughes has suggested some of his players have struggled to come to terms with the club's new status and ambition.
Since the takeover by the Abu Dhabi United Group, City have been linked with a host of world-class stars.
In addition, Hughes has begun restructuring the club since he took over from predecessor Sven-Goran Eriksson in the summer.
City's results have so far not reflected the ambition of owner Sheikh Mansour Bin Zayed Al Nahyan, a member of the Abu Dhabi royal family.
They are currently in 13th place in the Barclays Premier League, just two points above the relegation zone, and they suffered a humiliating 3-0 FA Cup third round defeat at home to Nottingham Forest on Saturday.
A number of players are woefully out of form and Hughes admitted some of them were struggling to cope with the new regime.
"Change is difficult for some people to cope with, others embrace it," he said.
"The acquisition of top-quality players is the big driving force behind it (the change)."
Hughes did not name names but the drop in performances on the pitch has been apparent to all.
The form of defenders Richard Dunne and Micah Richards - two of City's best players last season - has been a concern while playmaker Elano has fallen out of favour.
However, Hughes dismissed out of hand suggestions he was considering stripping the captaincy from Dunne.
"That is not up for discussion at all," he said.
When asked to comment on suggestions Richards was carrying too much weight Hughes joked: "Are you going to ask him?"
City face an important few weeks with matches against Wigan, Newcastle, Stoke and Middlesbrough following tomorrow's trip to Portsmouth.
Hughes hopes to have strengthened his squad sufficiently during that time with England left-back Wayne Bridge already signed up, although bids for Blackburn striker Roque Santa Cruz and West Ham duo Scott Parker and Craig Bellamy have been rejected.
"It is not going to happen overnight but it is a long drawn-out process to make the club stronger," he said.
"It is still early days in the development of the team but we are going in the right direction.
"Managers will always go with players they feel they can trust and have had experience of in terms of technical ability and their character.
"But there is no minimum or maximum amount (of signings). If players are available to improve us we will try to bring them to the club.
"We have made a good start with Wayne and we are looking to add to the quality we already have here.
"Wayne is one of the top left-backs not only in this country, but in Europe as well.
"He has the right quality, he has the determination and the drive to show people exactly what he can do on a regular basis. That's the type of player we need here."
Bridge is expected to make his debut tomorrow and Nedum Onuoha has recovered from a hamstring problem but doubts remain over forward Robinho (thigh) while midfielder Stephen Ireland is suspended.
"We are a bit light with the injuries we have at the moment," admitted Hughes.
"Fratton Park is always a difficult place to go. They are having a little bit of a difficult time themselves at the moment and they will be looking to turn their season around.
"We have to make sure we are up for the challenge."
