"Everything up until this point, there was a little pain and discomfort involved," Darvish said through his interpreter, when asked why he'd added the back workouts. "I was trying to see alternatives."
Darvish has not pitched for the Cubs since May because of right triceps tendinitis, and the team will wait to see how he feels on Sunday before deciding on the next step in his rehab.
"Now that I'm pitching, I'm very optimistic about this process," Darvish said.
Cubs manager Joe Maddon can tell the right-hander is feeling better.
"He seems a little more upbeat," Maddon said. "His smile was easier. I try to read body language and faces -- and when you ask pitchers how they're feeling, they reveal what's going on, and normally it is the smile. I took that as a good thing."
The only negative in Darvish's rehab of late were comments by ESPN's Alex Rodriguez during last Sunday's broadcast. Rodriguez suggested Darvish should be in Arizona getting treatment, not with the team.
Cubs president of baseball operations Theo Epstein has communicated with Rodriguez since then, but Darvish said he didn't see the text messages between the two. Would Darvish want to talk to Rodriguez on Aug. 12, when ESPN broadcasts the Cubs' game against the Nationals?
"If he sends me a text message or something, I'll keep it and maybe take a screen shot and print it out and frame it," Darvish said through his interpreter.
Then, Darvish added in English: "I'm not joking."
So there's no misunderstanding, Darvish was being sarcastic.
• On Friday, Pedro Strop got the save, subbing for Brandon Morrow, who is on the disabled list because of right biceps inflammation. How does Maddon pick who will close?
"[Baez should] just continue with pitch selection, just force the pitcher into the zone more," Maddon said. "That's it. He's using the whole field. You saw the home run, opposite field, into the wind [on Friday]. You saw the play at second base, the play at third base. You've seen the baserunning. When you sit down and work with him, there's not a whole lot in the other parts of his game [that need work], other than hitting."