"Continues to gain strength," said Farrell. "He feels more stability in each throwing session that he goes through. Today is planned to be another aggressive one for him. We would hope that after today, and tomorrow being a little bit of a normal recovery day for him, that we're getting closer to the mound and hopefully we'd be able to incorporate some work, whether that's continued crow hop off the mound or actually getting on it. I think the mound is definitely getting closer here."
A telltale sign for Buchholz will be when he can crow hop and throw the ball with 100 percent intensity.
Buchholz said that Sunday was his best day in that regard, as he estimated he threw at about 80 percent intensity.
"The highest intensity I've thrown was today," Buchholz said. "It was to the point where I'm not hoping or thinking something's going to happen or I'm going to feel something when I throw. I'm able to let loose a little bit more right now, and even if it's only four throws that are at a higher intensity than the day before that's encouraging for me, for the next time I go out and throw, to go out and play long toss. To get into it a little bit more."
Buchholz will sit down with Farrell and the training staff on Monday to determine the next step.
"It felt good [Sunday]," said Buchholz. "I played pretty extensive long toss. It was good. The last two days have been really good for me. Moving forward, we're trying to map out what I can start doing. I'm sure we'll talk about it tomorrow, because it's an off-day for me."
Buchholz said that this is the best he's felt since before the All-Star break, when he pushed a little too hard and had a setback during a throwing session in Oakland.
"I haven't felt this good throwing since there was a day in Seattle I played catch and didn't feel anything," Buchholz said. "That's sort of where we're at now. That's why I don't want to do too much at one time just to let everything figure itself out. Let the muscles start working together again. Yeah, obviously the next step is to get off the mound a little bit for a touch and feel type thing just to get back on the rubber."
Once he is able to throw off the mound two to three times without restrictions, the Red Sox could send him out on a Minor League rehab assignment.
Buchholz, who last pitched for the Red Sox on June 8, is 9-0 with a 1.72 ERA in 12 starts.
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. Michael Periatt is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.