"It's getting there ... it was my first time off the mound in eight weeks," Estes said. "You can't expect to throw 100 [mph]."
Instead, Estes reported no pain in the left thumb he fractured in a fall at AT&T Park on May 30 when he fell on the stairs that lead from the visiting clubhouse to the dugout. He wore a splint on his left thumb for seven weeks.
That splint came off a week ago and Estes -- who threw all fastballs -- will throw another bullpen session on Wednesday followed by a simulated game Tuesday while the Padres are in New York playing the Mets.
The simulated game would likely take place at Class A Lake Elsinore.
If all goes well, Estes will pitch for Lake Elsinore on Aug. 9 in the first game of a Minor League rehabilitation stint.
Estes was 1-1 with a 3.33 ERA in five games, including four starts, before he suffered the injury. He helped stabilize a rotation that, at the time, was devoid of Jake Peavy and Chris Young because of injuries.
Estes doesn't imagine any setbacks moving forward, though he said he has yet to test the thumb by throwing any curveballs. That could come as soon as Wednesday, though.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.