As of Darius Slay‘s most recent remarks on his situation, he had not yet been moved to the Bills’ reserve/retired list. That is now taking place, though. 
Buffalo is making the expected procedural move, Ian Rapoport of NFL Network reports. This ensures Slay will not play for the Bills while opening a roster spot in the process. The team has not waited long to find a replacement in the secondary.
Darnell Savage has been claimed off waivers, per Rapoport. Savage joined the Commanders in September shortly after his Jaguars release. After not seeing much in the way of playing time in Washington, however, the former first-rounder requested to be let go. The Commanders granted it, moving Savage to the waiver wire. Instead of reaching free agency for the second time during the season, he will now (presumably, at least) head to Buffalo. Both moves are now official, per a team announcement.
Slay’s Steelers tenure came to an end after Asante Samuel Jr. signed with Pittsburgh. Reversing his intra-Pennsylvania switch from the offseason seemed to be in store at the time, and Philadelphia put in a waiver claim. With a reported mutual interest between Slay and the Eagles regarding a reunion, many have pointed to the parties reconnecting as a possibility. For now, though, Slay’s rights still belong to the Bills.
Savage, 28, made eight appearances with the Commanders but played only a rotational role on defense. His workload was set to shrink even further with Will Harris returning to the fold. Given this move, Savage will have a brief opportunity to carve out a role of some kind in Buffalo. With the Bills sitting at 8-4, he will at least have a much better chance of seeing postseason action compared to finishing out the year in the nation’s capital.
The Bills currently rank fist in the NFL in passing yards allowed per game (163). Issues against the run could remain down the stretch, but the team’s secondary will be a unit continuing to face high relatively high expectations. Savage could chip in for the closing stages of the campaign and in doing so provide a slight boost to his free agent value.