Darrell Robertson was added to the Patriots practice squad November 17 and never played in a game. He stayed on the practice squad about six weeks, and was then released.
Brad Listorti was added to the Jets practice squad for about two weeks and never played in a game, and then released.
The Chiefs picked up the cast off practice squad linebacker.
The Patriots picked up the cast off practice squad tight end.
When the Chiefs picked up the player released by the Jets, there was a comment that that spoke really well about the depth of the Patriots. If you see no parallel between the tight end transaction, you might not be trying very hard.
On whether Pioli is intimately familiar with Robertson's development, well, Robertson was on the practice squad for about six weeks. Then Pioli left. There was no off-season program, drills, pre-season games, or things like that, nor a long period of time to watch his development.
There are always lots of players like this that the Patriots pick up every off-season, and plenty more that are released. A few make it on other teams, like Dane Looker or Robbie Gould or Sean Morey. It's tough to project how other players on the team will progress based on these practice squad transactions.