As a result, a dual registration arrangement has been agreed for Lewis to turn out for Cinderford.
Meanwhile, Field, who has been a regular in the Gloucester United side competing in the Aviva Premiership A League this season, has signed a one year contract which will allow him to play for both Gloucester Rugby and Hartpury RFC.
"We're in the fortunate situation of having four quality scrum halves in the squad. But, I can only select two of them for each match.
"However, the nature of the modern game is that injuries happen. It's a fact of life. While they're all fit and raring to go at the moment, that could change at any minute.
"You can train as hard as you can but it's not the same as playing in matches. It's important that they all get competitive rugby on a regular basis.
"We've got excellent relationships with both Cinderford and Hartpury, and have reached agreements with both where Dave and Brad can turn out for them when appropriate. It's a good solution for all parties."