"I think I should be pitching here in September," Hammel said. "I'm pretty sure about the September expectations that we have right now, so hopefully the first week. That would be very feasible in my mind."
The right-hander owns a 3.54 ERA this season despite lingering issues in the knee that eventually led to surgery.
Hammel said a strong week has led to increased optimism. On Monday, he would have been "scared" or apprehensive to project such an early return.
"It was moving too slow for me, but in the last three days we've made great strides," Hammel said. "It feels good. Definitely feels much better, much improved."
Since the surgery, Hammel had only done light running and cone drills before Saturday. He said his "range of motion isn't quite fully there" and strengthening the knee remains a challenge, but it was "coming along."
Saturday's test was expected to be an important barometer for how close Hammel is, with manager Buck Showalter saying he was "anxious to see how that goes."
"I really don't know how it's going to feel," Hammel said. "I haven't really extended the knee so much."
Showalter said Hammel could throw off the mound for the first time on Monday if everything went smoothly on Saturday. Hammel was hopeful he could stay with the team during the process rather than travel to Sarasota, Fla. In Baltimore he can bounce ideas and mechanical issues off of pitching coach Rick Adair if he needs to.
Wherever he ends up, Hammel said he doesn't think he'll need a lot of time to rebuild his arm strength.
"My arm doesn't need too much to get into shape, it'll be based on the knee," Hammel said. "I've been throwing all ready. So it's not like it's going to be a shock to the system to start throwing again. So I think we're in pretty good shape right now."