Anderson, who underwent Tommy John surgery last July, allowed four runs on seven hits in four innings for Sacramento, but Melvin was encouraged by the reports.
"You look at the numbers and they weren't great, but what we're looking for at this point is how he feels afterward," Melvin said. "And he feels great today. So that's kind of the first step."
Melvin said Anderson touched 93 mph on the radar gun, a surprisingly high figure in just Anderson's second rehab start, during which he threw 53 pitches.
"I was surprised he actually hit 93," Melvin said. "Your first couple of times out, there's always that reluctance to really let it go. I know he's a guy that throws in the mid-90s, so I was pleasantly surprised to hear that the velocity was up to that point."
Much more significant to Melvin, though, was that Anderson was feeling well.
The lefty is scheduled to throw a bullpen this week and then make another rehab start, although a specific timetable has not been laid out.