I think it comes down to Lloyd's price. A 31 year old WR with a less than consistent track record and numerous character concerns can't expect a top tier contract.
Patriots could be a fit for Brandon Lloyd because of McDaniels - The Boston Globe
Maybe McDaniels really is "the Lloyd whisperer" but when other players are questioning his value as a good teammate and some have openly questioned whether he may be bi-polar, you probably don't want to lock up such a player in a long term expensive contract.
Plain and simple we need a #1 WR next season. As a short range slot receiver we are set at #2 with Welker, who would be a great #1 if he were taller and could stretch the field deep. Lloyd would be an improvement in the deep department over what we have, but there may be much better options out there for a long term solution.
Signing Lloyd to a reasonable contract if they don't share the concerns of other teams and players would make sense if there's some concern about having Welker for the long term, but I think they may have their eye on other solutions for a #1 deep threat receiver.