Axford's MRI on Thursday revealed there was no damage beyond a shoulder strain, John Shea of the San Francisco Chronicle reports.
Axford's MRI results yielded good news Thursday, though he'll refrain from throwing a baseball for the next week while he continues to recover. Santiago Casilla appears to be the early favorite to lead the A's in saves this season, with Ryan Madson, Sean Doolittle and Ryan Dull also in the mix.