You have a point, but the Cards need some offense to make up for the walking (and not playing) wounded key players on the roster. I would prefer waiting till the end of the season to bring Adams up for a taste, but if the DL list stays populated with most of the Cards offense, something will need to be done to offset the loss of offense (and defense). And I'm not fully comfy with the notion that Puma will not make another visit to the DL list before the season ends.
As for Puma in RF, it might be easier on him than the infield ... one never knows for sure. What's best depends on precisely what is the source of his ailing. At 1B he gets caught having to make a lot of sudden and awkward moves and twists which could be more deleterious to his bod than the occasional running he needs to do to play RF.