Harnish was the 2012 NFL Draft's "Mr. Irrelevant," a title given to the last player selected overall. He played his college football at the University of Northern Illinois, where he was coached by current Minnesota Golden Gophers head coach Jerry Kill. He was inactive for several games as a rookie before being released and re-signed to the practice squad, and he spent the entire 2013 season on the Colts' practice squad as well.
The prevailing wisdom is that the signing of Harnish is a sign that Teddy Bridgewater's ankle might prevent him from playing on Thursday night when the Vikings travel to Green Bay. If that's the case, the team would have to promote quarterback McLeod Bethel-Thompson from the practice squad to serve as the backup quarterback.
No word at this time as to who was released to make room for Harnish on the practice squad. The Vikings released wide receiver Donte Foster from the practice squad to make room for Harnish.
When final cutdown day came around back in August, there were numerous people that were inexplicably livid that the Minnesota Vikings chose to keep three quarterbacks on the roster, largely because one of those three quarterbacks was named Christian Ponder. Now, just five weeks into the season, the Vikings have four quarterbacks on the team between the regular roster and the practice squad, and it appears that Ponder might be preparing to start.
Offensive coordinator Norv Turner reportedly "pounded the table" for this team to keep three quarterbacks on the roster. Probably a good thing that he did that.