OWINGS MILLS, Md. -- The Baltimore Ravens sent a letter this week to season-ticket holders, suite holders and sponsors about the number of no-shows at M&T Bank Stadium this season, citing a protest during the national anthem as one potential reason.

The letter, which was signed by team president Dick Cass, mentions that there have been empty seats in the past when the Ravens have struggled on the field. But this year is different, with Baltimore in the midst of a playoff race.

"The numbers [of no-shows] are higher, and it is noticeable," Cass wrote in the 656-word letter. "There are a number of reasons for the no-shows, but surely the one-time protest in London has been a factor."

Ravens president Dick Cass acknowledged in a letter to fans that the team's "one-time" protest during the national anthem in London on Sept. 24 has been a factor in the number of no-shows to home games this season. AP Photo/Matt Dunham

The Ravens' first protest as a team occurred in London on Sept. 24, when more than a dozen players knelt during the national anthem before the first NFL game of the day. That began a daylong chain of protests in the wake of President Donald Trump's critical comments and tweets about protests during the anthem.

The following week in Baltimore, the Ravens knelt in prayer before standing for the anthem. Fans at M&T Bank Stadium booed the players when they took a knee.

The team has not protested since.

"We have responded to your concerns about the protest by re-doubling the efforts of both the organization and our players to make the Baltimore area a better community," Cass wrote.

According to Cass, the Ravens reached out to a number of fans who wrote to the team or called about the protest. Cass also personally made a number of phone calls and met with some fans, the letter stated.

"We want the Ravens to continue to be a strong, unifying force and source of pride in our community," Cass wrote. "When the Ravens win, we can bring families and the community together. We've done that before, and we can do it again.

"In light of recent events, we are also reminded that winning alone is not always enough to make the Ravens the unifying force we want to be. We don't take your support for granted, and we know that we must continue to earn your respect and investment in us."

In the letter, Cass underscored the history of success, including two Super Bowl championships, and the team's commitment to the community.

The letter was sent before Baltimore finishes out the regular season with home games against the Indianapolis Colts and Cincinnati Bengals. If the Ravens win out, they will clinch their first playoff berth since 2014.

"I think they're starting to get excited about this football team," coach John Harbaugh said after last Sunday's win over the Cleveland Browns. "So it should be fun in our stadium against the Colts next Saturday night."