Title-holders Muang Thong are four points behind 2011 champions Buriram, who have a game in hand. While Muang Thong will have a tough assignment at home to BEC Tero Sasana tomorrow, Buriram should comfortably seal a home win against relegation contenders Bangkok United.
"We are looking forward to the match and we want three points," Buriram coach Scott Cooper said. "We must create confidence before we meet Iran's Esteghlal in the AFC Champions League quarter-finals."
The Thunder Castle are at full strength, with Prathum Chuthong, Jakkraphan Kaewprom and Charyl Chappuis returning to training after being sidelined through injuries.
While Buriram are the only unbeaten side this season, Bangkok United have lost all their away matches.
As for Muang Thong, it will be Winfried Schaefer's second match in charge of the Kirins after he resigned as national coach.
Schaefer got off to a bad start two weeks ago when his men lost 1-0 at Bangkok Glass.
The former Cameroon coach's task looks more difficult as he will be without suspended midfielders Datsakorn Thonglao and Phichitphong Cheuichiu.
"I believe other players are good enough to replace them although we will have to change some tactics," Schaefer said.
"We did not play well in the previous match and we have learned from our mistakes in the match.
"There is still a long way to go and Sunday's match should be a good opportunity for us to regain confidence. Our spirit looks good but we have to improve our performance if we want to retain the title."
BEC Tero Sasana will be without striker Cleiton Silva, who is suspended.
BEC manager Thanya Wongnak said: "We are not worried about playing Muang Thong because the pressure will be on them. We have Rene Daesayere, who was coach of Muang Thong, and his knowledge should be helpful."