Rainbows head coach Fred vonAppen said after yesterday's practice that Lacey voluntarily quit the team over a disciplinary dispute.
"Basically, he was late to weight training," vonAppen said. "He then decided to leave early without finishing his lifts. Then on being admonished for it, he had some lip.
"We said, 'OK, we'll take a little punitive action on the field.' He thought the punitive action was excessive and he asked to see the head coach.
"So he came up and explained his plight to me, and I said, 'Do the running.' He said, 'I'm not going to.' So I told him to get his ass out of here."
If Lacey doesn't return - and it appears he won't - he will be the third player to leave the program this season. The other two are offensive tackle Hauoli Wong and running back Brendyn Agbayani.
VonAppen probably would have allowed Lacey back on the team if he had returned yesterday. He said Lacey would have been suspended for this week's game with San Jose State.
"I don't want to make a big deal out of this," the first-year coach said. "Senior players from former regimes often don't handle transitions like this one very well."
In three previous seasons Lacey had 36 receptions for 302 yards and three touchdowns.
Although starting seven games last year as a junior, this season Lacey has not started. He was tied for eighth on the team in receptions with five for 81 yards and no scores.