One thing that may or may not have colored the futures of both Mike Rucker and Julius Peppers is the sudden lack of availability of other ends. Dwight Freeney (Colts) and Justin Smith (Bengals) have been franchise tagged, meaning that it'll probably be well into April that either is signed to a long term deal, likely to be very lucrative and expensive. With the pair of tagged veterans being added to Kansas City's Jared Allen (a restricted free agent who asked for a trade this week), there will be a minimal amount of elite pass rushing available. The best option at this point is DE/LB phenom Adalius Thomas, who may set the price tag for both positions this year. Fewer free agents of worth being on the market means overspending for second and third level guys.
Initially, that would go against Rucker - the team could get $4.4 million in cap space by cutting him outright, giving enough room to start free agency without getting a Peppers deal done. Extending Peppers' contract would knock a good deal of cap space off the books - his current cap charge is $14 million, and the team can't get that cap relief until they strike a deal. Peppers' camp is likely to wait until the other deals are signed, since he's not a free agent.
But without other options on the table, the team may have decided that putting a high pick behind Rucker and extending his deal would give the team the relief they needed, at a cost effective price - Rucker's in the final year of his deal, so future cap spreading doesn't compound a past contract's problems, so most of the restructuring would mean savings.
Therefore, with Rucker expected back and the team looking to find a cheap backup, Al Wallace and his problems defending the run were gone for immediate savings. Since the team couldn't find anyone reasonably priced to replace Rucker, they simply stay with Rucker. The hard part will be waiting out the Peppers contract and that savings.