Michael Mathis has stepped down as president and chief operating officer of MGM Springfield, and his replacement is slated to come from one of MGM Resorts’ Midwestern casinos.

MGM Northfield Park President and Chief Operating Officer Chris Kelley is expected to take over for Mathis pending regulatory approval, MGM Resorts announced Tuesday. MGM Springfield Vice President and Chief Financial Officer Courtney Wenleder is also leaving her position at the casino.

The Springfield shake-up comes amid months of poor gaming revenue.

December’s $18.9M gaming revenue was the worst month for MGM Springfield since it opened in August 2018, down from November's $19.9M, its second-worst month.

The Western Massachusetts resort’s first-year gaming revenue was $144M below projections.

Mathis blamed December’s poor performance on inclement weather. But that same month, Encore Boston Harbor posted its best month for gaming revenue since opening in late June.

Mathis had served as president and COO since 2014, before the Massachusetts Gaming Commission awarded MGM Springfield a gaming license. Mathis will now serve as senior vice president of business development at MGM Resorts, MassLive reports.

Kelley has been with MGM since 2017, starting as vice president and CFO of MGM Grand Detroit. He transitioned to MGM Northfield Park in Ohio last spring.

“We are excited to have Chris lead the MGM Springfield team,” MGM Resorts International Portfolio President Jorge Perez said in a statement to MassLive. “Chris’ experience in Ohio, rebranding and integrating a property and introducing MGM to the community, will be an asset for Springfield as we continue to work closely with the community and strive to not only be a world-class entertainment destination, but also a good corporate neighbor."