I was thinking more of 2B, with Owings taking over SS.
I know that Ahmed has gotten a few singles and a double recently, but a little better than worst is still not good.
But according to everything I've researched about Lamb, his position is 3B. No record of his playing any other position.
If Tomas continues to dominate at-bat (and it looks like he will) and without major changes to move him to the outfield, Lamb is not serious compeition at 3B, no matter how good he looked for a brief time.
As the season progresses, the D-backs need to make some decisions and aim for a more traditional roster of starters and bench players.
If not, they will face the same problems as the Suns with their 2- and 3-Point Guard lineups. Eventually, the players who share positions will react.