Brown (19-11) weighed 172.5 pounds on his first attempt. According to UFC president Dana White, in a miscommunication between Brown and the California State Athletic Commission, the fighter was informed he could not attempt to make weight a second time. Although he originally was to be fined 20 percent of his fight purse, with 10 percent awarded to Lawler, the fine was rescinded after a discussion with the commission.
ESPN.com originally reported that Brown was given two hours to cut to the allowed 171-pound limit but elected to forgo the effort.
Brown is still eligible to claim the No. 1 contender status with a win Saturday, as well as UFC Fight Night bonus money.
The welterweight bout, which headlines Saturday's UFC on Fox event at the SAP Center, will determine the next title contender at 170 pounds.
Lawler (23-10) successfully made weight at 171 pounds. He challenged current champion Johny Hendricks for the vacant UFC title in March but lost via unanimous decision. He defeated Jake Ellenberger via third-round TKO two months later at UFC 173.
All 24 fighters set to compete in Saturday's event made weight except Brown and female strawweight Juliana Lima. Lima (6-1) weighed in at 116.5 pounds, a half-pound over the allowed limit.