The Kiko Alonso-LeSean McCoy swap was a stunner for the Bills and Eagles, and it will likely reverberate outside of both of those markets. If you're looking for a linebacker or a running back in free agency—and I'd bet money the Falcons are targeting both—you've got to stand up and pay attention.
Vaughn McClure at ESPN has an excellent breakdown of what it might mean for the Falcons, particularly when we're talking about linebackers. McClure has said he anticipates the team will be in the market for a middle linebacker, and that market may be thinned out by a team with a fresh need.
As McClure notes, the Bills are now likely in the market for a linebacker, and that means Jets free agent David Harris could very well be heading there. The Falcons could explore cheaper options like Mason Foster, who McClure mentions, and there's reasonably cost-effective options like . If you're looking for pass rushers who can play linebacker in a pinch, of course, there's plenty of options, but that market was already going to be competitive before the Alonso-McCoy swap.
The Falcons aren't going to force it, per McClure:
Don't expect the Falcons to get involved, if such occurs. Yes, Harris is an impact player who would fit nicely in coach Dan Quinn's scheme. Plus Quinn, a former assistant with the Jets, is familiar with Harris' talent. However, the Falcons surely won't overpay for any player -- not a standout linebacker or even an impact pass-rusher.
McClure's breakdown is pretty through on the linbacker side—and that's the important side— but I feel like I should add in the cascade effect that could occur at running back. The Bills now have McCoy and have kicked C.J. Spiller to the curb, adding another back to a market flooded with complementary types, and the Eagles are said to be looking for a feature back. The Falcons are probably shopping for more of a Spiller or Justin Forsett type than, say, Mark Ingram, so this isn't likely to have a major impact. But do keep an eye on the Eagles, given their dearth of options at running back.