In the previously announced main event at the MGM Grand Garden Arena, welterweight champion Georges St-Pierre of Montreal meets No. 1 contender Johny (Bigg Rigg) Hendricks.
The UFC bills the Lawler-MacDonald matchup as "old school meets the new breed." The 24-year-old MacDonald is ranked third among 170-pound contenders while the 31-year-old Lawler is No. 9.
MacDonald (15-1) is coming off a decision over Jake (The Juggernaut) Ellenberger that stretched his winning streak to five.
But the Seattle bout was booed by the crowd for lack of action and UFC president Dana White made no secret of his dissatisfaction at both fighters.
Some saw the win as a technical triumph by MacDonald, who used distance, a stinging jab and front kicks to keep the hard-hitting Ellenberger at distance. But not the UFC boss.
"That fight sucked so bad," said White.
"I don't think he moved down the (rankings) ladder but do you think anybody's screaming to see him in a fight again? ... We live in a business unfortunately where you're as good as your last fight," he added.
Lawler (21-9 with one no contest) is 2-0 since returning to the UFC after an absence of more than eight years. He is coming off KO wins over Josh Koscheck and Bobby Voelker.
The power puncher has upped his game since training at American Top Team in Florida and will likely pressure MacDonald into showing what he has got.
MacDonald is seen as a possible future 170-pound champion, although he and St-Pierre have both said the two Tristar Gym members won't fight each other.
The native of Kelowna, B.C., who now fights out of Montreal, is 6-1 in the UFC.
In other news, Canadian light-heavyweight Ryan (Big Deal) Jimmo will face Jimi (Poster Boy) Manuwa on a televised card Oct. 26 in Manchester, England.
Jimmo (18-2) is 2-1 in the UFC, defeating Igor Pokrajac by decision last time out. Jimmo, a native of Saint John, trains out of Edmonton.
Manuwa, an American fighting out of London, has won all 13 of his fights including two in the UFC.