There is an article in the Seattle Times that takes a look back at how and why Seattle waived Glow and why he probably ended up with the Colts.
Of course one reason is because of a roster crunch - trying to work with the roster leading up to a game dealing with multiple injuries. But it appears Seattle was also wanting to avoid a bigger cap hit and wanted to void his rookie contract after he qualified for performance escalators.
It also states that Glow was on the Colts radar because of Ed Dodds - who had previously been in Seattle's front office.
The article is linked below:
https://www.seattletimes.com/sports/...-the-seahawks/