I disagree.
When you offer a player there should be some kind of goal visible you try to accomplish in a deal. Putting players out for a market tryout is nice, but what should someone bid for him ?
Youth?
When you want youth for a 27yr old you mean a rookie contract which not only makes salaries hard to match, but nobody would give a young player than looks like he can get better than VK in a season or two, and you wouldn't trade VK for a young player that can NOT get better than VK in a season or two.
Veterans (meaning players AFTER the rookie contract)?
Not what you ask for, but maybe a good player at a different position would do. My gut feeling is that VK won't go for an older player unless it's a superstar (Pettit, Howard, that's about it. But none of those would go for VK)
Picks?
There is zero guarantee how a pick will pan out and I doubt you'd take the risk of a non-lotto pick, and as the standings get clearer later in the season it's still a big unknown we're talking about here. My guess is that VK won't go for a pick that couldn't be #1 (but again, no pick looking it could get #1 pick would go for VK)
So here's the dilemma. By putting out VK with about zero chance he'll be traded you won't get any information on his market status. Maybe a few mediocre offers and maybe someone even breaks the bank and throws in a lottery pick for a chance to win now (which of course you think is nice but will never accept).
As long as you treat a one-dimensional top scorer like the new coming of real superstar (like GP) don't expect any offers you like in return ...