Yep! Think at this point, he is far more valuable to the team than Walker. That said, maybe since they called Bird up so quickly, they first want to make sure he can hit for even a semblance of an average and also the ankle is really healthy If he proves to be healthy and hitting and Walker still pretty much struggling, they could DFA Walker then and bring Torreyes back up.
"Always look on the bright side of life!"
Eric Idle