Looking at the RFA tenders this year, you see that they are:
$712,000 (lowest compensation = original round of players' selection)
$1,550,000 (middle compensation = 1st round pick)
$2,069,000 (highest comp = 1st & 3rd round pick)
Assuming FA continues as it has in 2007 (with a CBA extension), when Schaub becomes an RFA after the season, the Falcons will have to tender Schaub at least at the middle level to probably prevent him from simply signing with another NFL team. The tender offers increased about 8.5% from 2005 to 2006, while it was about a 4.5% increase from 2004 to 2005. I'm not sure how much it will increase from '06 to '07 (I'd guess it'll be closer to 5%), but even with such a modest increase, the Falcons will likely have to invest anywhere between $1.63 million and $2.17 million in Schaub, just for the purposes of shopping him.
Right now the Falcons have $533,000 invested in Schaub, and that's a huge amount to invest in a backup player even if it's for the sole purpose of trading him. Sure, that high cap hit goes away once Schaub is traded, but no one knows how long it would take to negotiate a trade for Schaub (if one is possible). It could be a week, or it could be a matter of months. That's basically $2 million more money the Falcons would have to clear under their '07 cap (if there is one of course) just so they can shop Schaub.
"Vincere scis, Hannibal, victoria uti nescis" -- Maharbal, 216 B.C.E.