Why hasn't Mike Thomas returned punts all year?

On Monday Night Football, Jacksonville Jaguars wide receiver Mike Thomas saw playing time at punt returner for the first time this season. This was a role for him the past two years and he was a proven threat returning the ball and key for field position. Through the first six games of the season, rookie receiver Cecil Shorts III was returning punts and was completely ineffective, even a liability at times.

On Monday, Thomas returned six punts for 37 yards including a 28 yard return that setup a field goal. Thomas also had some other long returns knocked out by penalties.

Conventional wisdom would tell you that Mike Thomas was the team's number one receiver, so he couldn't be risked on punt returns. That's fine and all, but when your passing game is already poor, you need all of the field position you can get. It makes more sense to put a reliable and explosive returner back there instead of a rookie who looks overwhelmed and continues to make poor decisions fielding the ball.

With the return of Mike Sims-Walker, it allowed for another viable wide receiving option and let Thomas go back to punt returns. In the return however, interestingly enough Sims-Walker dominated the snaps for the Jaguars receivers playing in 58 snaps. Jason Hill, who led the team in receptions and targets for the night, played 44 snaps while Mike Thomas played just 30.

So... why wasn't Mike Thomas returning punts all year long again?