Winfield led the team in Matt Bloomfield's absence last term before his departure to Shrewsbury to leave Ainsworth to ponder which player will take the captain's armband this time around.
Stuart Lewis led the side in Tuesday's friendly victory over Staines and looks like the obvious favourite to do so again when the League Two season begins on August 3.
"Stuart's leading us at the moment and he's come back (for pre-season) like you wouldn't believe," Ainsworth told the Bucks Free Press. "He's one of the key performers in our team.
"Whoever leads us out against Morecambe will be a really proud man. Stuart's just as proud at leading us out in pre season games. He's a great leader and he's got the respect of the boys out there.
"I'll have a think about it. Everyone's a captain out there."