I have to think his knee isn't healthy for him not to draw more interest from better teams.
I think that has more to do with how teams can sign players. Look at Barbosa. He could help a lot of teams and is clearly healthy and yet only got the vet min.
I'm sure some teams are wary of MPs knee, but the going rate for players not yet signed seems to be "vet min".
Either way (knee concerns or state of the NBA), the Cs should be signing him. We know he helped us last year, he fit in with the players and the system, and we have a clear need for guarding bigger tough wings like Wade, LeBron, Joe Johnson, Wallace, Carmelo, Granger, George, Jackson, Ginobili, etc..
I'm very frustrated that with an open roster spot we are not signing him costing so little money...worse case scenario we just cut him