Anderson allowed six earned runs on six hits with four walks and three strikeouts in just 3 2/3 innings on 80 pitches, but not once did he feel pain in his right ankle, which put him on the disabled list May 2.
"I feel good today," said Anderson, back in the A's clubhouse Monday. "You go from pitching in a game where every pitch and every out matters to pitching in front of 500 people in San Antonio, where you just kind of want to get your work in, and I was able to get my pitch count up.
"It was good to get in a game and come out today feeling well. It's not like last time where I came out and couldn't really walk."
So long as Anderson escapes Monday's workouts without aggravating the ankle, he'll likely be in the clear to return to the A's. The lefty could be reinstated from the DL as soon as Friday for a home start against the Royals. Right-hander Dan Straily, Wednesday's starter, is expected to be the odd man out when that happens.
"The most important thing about Brett's outing, even though the numbers didn't look great, is the fact that he felt good," said manager Bob Melvin. "He didn't feel anything with his ankle, and that's pretty much what we were looking for. We'll see how he feels today, and then I could potentially have a decision tomorrow on where we slot him in."
Anderson was 1-4 with a 6.21 ERA when he went on the DL, numbers that reflect struggles felt by Oakland's entire starting staff, which entered the day with a 5.17 ERA, fourth-highest in the American League.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.