Churning the bottom of the roster is what good GMs do, trying to improve on the team's depth and maybe find a hidden gem. We've had a lot of injuries, so we have more of a need. No one gave a thought to Schneider signing Ben Brown back iin late August, but there he was, getting into the game vs. the Panthers.
As for Tavon Austin, he and Geno go way back to their West Virginia days. I would think that it's possible they worked him out as a favor to Geno. Tavon had those combine numbers, 4.3 40, but he also had the numbers to back him up, #1 and #2 in NCAA all-purpose yards in 2011 and 2012. He was the 8th pick in the draft but never became a star.
Sean McVay did not care for Austin's game at all. You would think that McVay would think of him as a real weapon with his speed, but he didn't hardly use him in 2017, and then the next year traded him to the Cowboys.