The Arizona Diamondbacks placed starting pitcher Luke Weaver on the 10-day disabled list and sent him back to Phoenix for an MRI exam Monday after he left Sunday's start with right forearm tightness. Weaver had allowed one run through five innings Sunday against the San Francisco Giants but showed discomfort after giving up a single to Buster Posey to start the sixth inning. "Just felt a little tightness in the forearm," Weaver told reporters afterward.