Yes. Tom Milone, Brade Meyers and Brad Peacock should all be able to step in the rotation, today, and provide approximate value to what Lannan brings to the table.
I figured this is what you were getting at, and I don't necessarily disagree, but you can't assume that. A couple of years ago it might have been okay to get what you can for Lannan and take a chance on any of these guys, but we're too close to the promises the FO is made for them to make that kind of move now. I think Lannan stays until one of the guys you mention have been up and pitched as well or better than him for at least half a season.
Unless of course you think Rizzo is going to go out and sign 2 FA pitchers.