Usually, an NFL team signing a player to their practice squad isn't that big a deal. Teams release and sign players to their practice squads at various points throughout the season.
On Wednesday, the Vikings re-signed Owusu. . .for the fifth time this season, counting his signing with the Vikings as an undrafted free agent back in May out of the University of California. This was made a bit more unusual by the fact that they didn't have to release Holmes, a rookie from Tulsa, in order to do it. Here's a chronological look at the entire thing.
-29 September - Vikings re-sign tight end Allen Reisner to the practice squad after releasing him to make room on the 53-man roster for Jerome Simpson; Holmes released
-5 October - Vikings re-sign Holmes to practice squad; Owusu released
-11 October - Vikings re-sign Owusu to practice squad; Holmes released
-18 October - Vikings re-sign Holmes to practice squad; Owusu released
-23 October - Vikings re-sign Owusu to practice squad; Holmes released
-29 October - Vikings re-sign Holmes to practice squad; Owusu released
(Owusu was also released towards the end of training camp and spent a short time with the Cleveland Browns before he was released and signed to be on the Vikings' practice squad. That's the fifth time, if you're scoring at home.)
After the injury to Chris Cook allowed the Vikings to elevate Reisner back to the 53-man roster, their re-signing of Owusu today means that they didn't have to release anyone. So, Holmes and Owusu are on the practice squad at the same time again for the first time since September 28.
The league apparently doesn't consider it to be an issue with stashing players. . .after all, both Holmes and Owusu have been subject to waivers every time the team has cut one of them. According to the 1500 ESPN article linked above, since the releases generally happen in the middle of the week, both players get a full week of practice squad pay ($5,700/week) for less than a week's work.
Hopefully both men will enjoy their new stability and can stay with the Vikings for the rest of the season. Honestly, though, in all my years of being a fan and actively tracking the practice squads, this is certainly one of the more unusual practices I've seen.