Joe Capozzi relays the following:

Reliever Scott Proctor began throwing off the mound last week — his first “bullpen sessions” since undergoing surgery on his right elbow in October to repair a partially-torn flexor tendon. “I started spinning off some sliders (on Monday),” he said…

Don't know that he will be good to go by the time pitchers and catchers report.  But that really doesn't matter, the team should have a very good idea about his recovery by the end of the spring.