Mickelson is coming off his second withdrawal of the season. Last week, he withdrew during the third round of the Valero Texas Open after pulling a muscle in his right oblique.
In a statement, Mickelson said he spent the weekend at home before flying to Augusta for two days of Masters preparation.
After playing nine holes Wednesday, he said he felt “pretty good,” was able to “swing fine,” and felt “sore as opposed to hurting.”
“I feel that to give myself the best chance at the Masters I have to play in Houston,” he said. “If I thought I would injure myself further I would have withdrawn from the tournament, but the last few days have been good.”