Union manager John Hackworth said:
"Truthfully, we have been in some conversations [with Knight],"
"But at the same time, we are looking at a lot of different countries and have vetted out many different centre back options.
"I would think it depends on how these next couple of games go and where we are. He's certainly one of the guys we're still considering.
"We still think we need to add a potential centre-back to our roster."
33 year old Knight joined Bolton in a £4m deal in 2009 and has gone on to make nigh on 150 appearances for the club.
Philadelphia Union can count Sébastien Le Toux among their ranks - a player linked with a move to Bolton Wanderers back in the Owen Coyle days.
If they want him, they can have him. No bother.