Let's start with his pre-college days when Williams was one of the fastest sprinters in the country.
Teddy Williams (American football) - Wikipedia, the free encyclopedia
Williams practiced football and track and field at John Tyler High School. As a senior wide receiver he suffered a serious ankle injury, that limited his scholarship offers.[2] He received a track and field scholarship for the University of Texas at San Antonio, where as a sprinter he was a four-time All-American, won nine Southland Conference championships and received four Southland Conference athlete of the year awards.Track and field Williams is also a sprinter. While at the University of Texas at San Antonio in 2009, he recorded a time of 9.90 seconds in the 100 meters at the UTEP Invitational, that ranked as the best under all conditions in school history and fastest time in the world that season. He already held the school record with his previous personal-best of 10.16 seconds, that won the 2008 Southland Conference title. He also helped the 4x100m relay team run a season-best time of 39.59 seconds in 2010.
Williams obviously went undrafted but still got a shot with the Cowboys which was sheer luck really.
Dallas Cowboys
In 2010 the Dallas Cowboys were having their training camp in San Antonio. Williams, who had just finished his senior season and still had one more year of eligibility in a different sport, got a tryout in part because he was attending a local school and because of the relationship between University of Texas at San Antonio's assistant Eric Roark and the Cowboys’ director of scouting, Tom Ciskowski.[3] Although he did not play football in college, the Cowboys were intrigued by his size/speed ratio and signed him as an undrafted free agent on July 31, 2010.[4]
At first the Cowboys weren't sure where to play him, trying him at cornerback before settling on wide receiver. He was with the team for the entire preseason, and was waived on September 4, 2010, before being placed on their practice squad. He was called up to the active roster on December 21, 2010. In the 2011 training camp, he was hindered by a hamstring injury he suffered after a collision with assistant Jimmy Robinson,[5] and was released on September 3. He spent the 2011 season on the Cowboys practice squad. He was re-signed to a future's contract on January 2, 2012.[6] In training camp, he was moved from wide receiver to cornerback, but couldn't make the team.
So where does Williams fit, at CB or WR? Neither, he will be a four phase special teams player according to Ron Rivera:
Teddy Williams - Carolina Panthers - 2015 Player Profile - Rotoworld.com
Panthers signed CB Teddy Williams to a two-year, $2.3 million contract. Williams keeps getting looks around the league, but he's played one non-special teams snap since entering the league in 2010. He didn't play college football. The Panthers described Williams as a "four-phase special teamer," and he should have the inside track on a 53-man roster spot.
Believe it or not but we all remember Williams from the 2014 Bears game the Panther won. He's the guy that hit PR Philly Brown early drawing a penalty that was declined after Brown picked up the ball and ran it back for a TD.
A boneheaded play by Williams but you can at least see his speed on display there. The Bears released him about a month later.
It would appear the Panthers are placing a lot of faith in Williams though he has done little stat-wise in the NFL. He has five special teams tackles the past two seasons, not exactly lighting it up. My guess is ST coach Bruce Dehaven went to bat for him, thinking as long as he has the speed he can mold him into a top gunner. We certainly need it.