Darvish was sharp in four of his five innings against Northwest Arkansas. He retired seven consecutive batters in the first three innings, but the right-hander had a more troublesome fourth inning.
Darvish walked the leadoff man, Ryan O'Hearn, then gave up a two-run homer to Mauricio Ramos and a single before escaping with a double-play grounder on the 25th pitch of the inning.
With a planned pitch limit of around 75, Darvish knew the fifth inning would be his last, and he breezed through it in just nine pitches. It would have been a six-pitch inning if not for Corey Toup's two-out blooper, which went only inches over shortstop Luis Marte's glove.
"In the fifth inning, I think I got a right feeling that I was looking for," said Darvish, who threw 47 of his 72 pitches for strikes. He only took three hitters to three-ball counts, walking one.
The Rangers haven't said whether Darvish's next start will be for the Major League club.
"It's nothing that I can say for sure at this point," Darvish said. "I'll see how I recover tomorrow and I'll talk to the pitching coaches and then we'll go from there."
The right-hander returned to the Rangers from Tommy John surgery on May 28 after missing the final two months of 2014 and all of '15. He made three starts for Texas this season before going on the disabled list with right shoulder soreness.
On Sunday, Darvish allowed a leadoff single to Terrance Gore in the first inning, then gave up a run on Corey Toups' sacrifice fly after Gore stole second and took third on catcher Kellin Deglan's throwing error.
Darvish got out of the inning with two swinging strikeouts, on a breaking ball and a 97-mph fastball, his fastest of the evening. Darvish's fastball was hitting 95 mph in the fifth inning.
In his previous rehab start, July 4 for Frisco also against Northwest Arkansas, Darvish threw 42 pitches over two innings, allowing two earned runs on two hits and three walks while striking out five.
Right-handed reliever Keone Kela also made his second rehab appearance Sunday, pitching a scoreless seventh inning. He allowed one hit and struck out two. Kela last pitched for the Rangers on April 19 before going on the DL with a right elbow impingement.