Suh's money only lowers with a trade or re-sign. Suh's FUTURE worth has nothing to do with not getting Verner and Byrd.
We restructured Suh for Bush, Quin and Levy and Tulloch in 2012/2013. A trade of Suh drops his number to 19 million dead money from 22. There was money available for Verner but they went with Tate over Verner. They could have made Byrd money available or backloaded Byrds contract (like the Saints did) and traded Suh too. The cap room was there for both of those guys but the Lions went with Tate and re-signs.
http://www.spotrac.com/nfl/new-orleans-saints/jairus-byrd/
3.5 million for Byrd this year. Lions could handle that contract even with Suh re-signed. In fact they could restructure Calvin for 3.2 million adding only 800k to his number ever year. That gives you Byrd 2014 cap number. And you want Byrd in 2015. Cut Jones, Houston and there would be no Ihedigbo signing. Or a restructure of someone. Lions have the room for that 10 million for Byrd in 2015 when you look at the cap committments for 2015. But they went with Tate and Ihedigbo and re-signs.