Angels manager Mike Scioscia said the right-hander had no problems during a 45-pitch rehab assignment Sunday night in the Arizona Summer League.
"He's excited," Scioscia said Monday before the AL West-leading Angels opened a three-game series in Texas. "He threw all his pitches, no pain, maintained his velocity ... had plenty of fastball. It's positive. We'll see how he comes out of the next couple days and add him to the rotation."
An All-Star last season, Santana is 1-3 with a 7.47 ERA in six starts this year. He missed the first six weeks of the season with a sprained ligament in his right elbow and has been out since June 12 due to an inflamed right triceps.
Santana was with the Angels on Monday and will throw a bullpen session Wednesday. If that goes well, Scioscia said Santana could be activated from the 15-day disabled list and pitch as soon as Friday.
During his latest rehab start Sunday night, Santana's fastball was clocked from 91-93 mph, just short of midseason form.
Santana went 16-7 with a 3.49 ERA in 32 starts last season. His return could be a major boost for the Angels.
"It's important to us," Scioscia said. "Not only do we need him back, we need him active and that's what hopefully we're moving toward. Your rotation is vital to any team, and having such a big piece out for so long has been tough."