Tim Sherwood
Sherwood signed a three-and-a-half year contract with Villa upon his appointment in February. Getty Images

Aston Villa manager Tim Sherwood's future cannot be 100% guaranteed as the club brace for a £150m ($233m) takeover and the exit of American owner Randy Lerner.

An unknown preferred bidder has been awarded a period of exclusivity to secure their purchase of the Premier League side a year on from Lerner putting the club up for sale.

Separate consortiums led by Chinese businessmen, former Arsenal captain Tony Adams, and ex-Chelsea executive Paul Smith are understood to be interested, as are a group from the United States.

While new ownership often brings substantial investment and breathes new life into struggling teams, it can also lead to instability within the senior positions with managers and directors often vulnerable to being part of a sea of change.

Villa chief-executive Tom Fox admits that while Sherwood is the preferred man now, his role could yet be subject to review. Sherwood kept the club in the Premier League and guided them to a first FA Cup final appearance since 2000 after joining in February having been hired by Lerner,

"The owner of the club is Randy Lerner and he was very supportive of the idea of hiring Tim Sherwood," Fox said. "He hired me, so if a new owner comes in is my position secure in that environment? Who knows, you're dealing in so many hypotheticals there I have no idea."

Despite having only been in charge for four months, Sherwood had planned to stage a significant overhaul in the summer following a campaign that though illuminated by a domestic cup final appearance was undermined by the threat of relegation for long periods.

With Lerner on the brink of leaving Villa, the American businessman is unlikely to invest in the transfer window this summer, leaving uncertainty over where funds for spending may come from should any takeover be delayed or even postponed.

Fox concedes the change of ownership could affect the club's dealings in the window but is hopeful the Villa hierarchy can match Sherwood's ambitions.

"It certainly creates a dynamic, I obviously can't deny that," Fox admitted. "Our owner has indicated he wants to sell and he's doing what he's doing on that side but clearly there is that dynamic that is out there.

"Will that have an impact on how we do things [in the transfer window] and how quickly we do them? Yeah, I can't tell you that it won't. I still believe we will be able to make the changes we want to in the summer to make the squad more competitive for the start of the season.

"One of the reasons we hired Tim was that he has an excellent track record at developing young players. He has a few young players at Villa that he is excited about. There are some players in the squad that he feels he may be able to further develop.

"I think we'll be able to do the business we want to do in the summer even with this other dynamic happening and I have a great deal of confidence in Tim's ability to get performances out of players we have."

Though the identity of the mystery favoured bidder is unknown, Fox has hinted that Lerner will only have considered owners who have shown an understanding and appreciation for Villa's status within English football.

"Randy bought the club because he is familiar with the area," he explained. "He went to Cambridge and he understands the history of the club. When we met he gave me a book of the history of Villa and he talks passionately about the club.

"I think Randy is looking for people who obviously have the financial means to buy it, the financial means to continue support and people who understand what they're getting which is a real jewel within the English game. I am sure those are all part of the criteria that he's looking for."