AJ was a stopgap signing. He's not a problem. He calls a good game and can toss out baserunners. His OBP is not that high but he does put the ball in play which is a change of pace from all of Salty's futile k's with men in scoring position.
Bench players should be able to run, throw and play a couple of different position. Hitting from a bench player is a luxury. The other skills are a necessity. Nava had an extraordinary OBP. Without that, he is a zero.
Showalter was patting himself on the back for his genius in gamesmanship for outsmarting farrell. The beauty of baseball is that brains has little to do with success. Many stupid people have been good managers.