Chicago Fire have offered a financial incentive for fans attending Wednesday's MLS match against Inter Miami, whose star player Lionel Messi could miss out through injury.
Chicago Fire have sold more than 61,000 tickets for the game at Soldier Field.
Seven-time Ballon d'Or winner Messi has missed Miami's past three matches.
Fire will give $250 (£207) credit towards "new memberships for the 2024 season" or $50 (£41) credit to "single-game ticket buyers".
They said fans would receive the credit "regardless of which players are able to make an appearance on the pitch".
A Fire statement read: "While we don't yet know the official status of Lionel Messi's availability for our match tomorrow, as there's never a guarantee that an athlete will play on any given night due to several factors, we understand that many of our fans may be disappointed if they don't get the chance to see him play.
"We realise that there will be many in attendance who are coming to a Chicago Fire match at Soldier Field for the first time, and we're excited to welcome them to the Fire Family and give them an opportunity to become long-term fans by creating a wonderful, fan-focused atmosphere."
Fire's highest attendance at Soldier Field 37,122, against LA Galaxy in their inaugural season in 1998.
Argentina's World Cup winner Messi has played once in six games for Miami since 3 September and watched their 2-1 defeat by Houston Dynamo in the final of the US Open Cup last week from the stands.
Messi, 36, signed for Miami in July after his contract with Paris St-Germain expired.