Walker (elbow, shoulder) threw at 105 feet Wednesday, but he has no firm plans to throw a bullpen session, Richard Morin of the Arizona Republic reports.
Walker is recovering from Tommy John elbow surgery he underwent in April 2018. As he was ramping up activity this past spring, the right-hander developed shoulder soreness and hasn't thrown off a mound since May. Time is running out in 2019 for him to help the Diamondbacks' starting rotation.