The Portland Timbers began construction at Providence Park this offseason on a $55 million-plus expansion project that is set to add approximately 4,000 seats to the stadium.

The project is a big step forward for the Timbers.

Portland has struggled to accommodate its demand for tickets ever since entering MLS in 2011. The Timbers have sold out every regular season game in their MLS history and currently have more than 13,000 fans on their season ticket waiting list.

The stadium expansion project will enable the Timbers to increase capacity at Providence Park from 21,144 to approximately 25,000. When the project is completed in 2019, the Timbers will be able to offer season tickets for 3,000 to 3,200 new season tickets holders. The expansion project should also benefit the Portland Thorns, who are the most well-supported women's club team in the world.

But given the substantial demand for Timbers tickets, the strong support of soccer in Portland and the growing interest in MLS throughout the United States, it begs the question: Is Providence Park a viable long-term home for the Timbers?

Throughout MLS, average attendance is on the rise. The league averaged a record 22,106 fans per game in 2017, which marked the first season in MLS history that the league had averaged over 22,000 fans per game. The 2017 season also featured 35 games with more than 40,000 fans in attendance.

While many MLS teams -- such as the Timbers -- play in smaller soccer-specific stadiums, there is a benefit to playing in bigger stadiums for teams that can support larger venues.

Atlanta United led MLS with an average attendance of 48,200 in 2017 by sharing Mercedes-Benz Stadium with the Atlanta Falcons, while the Seattle Sounders averaged 43,666 fans per game last season by sharing CenturyLink Field with the Seattle Seahawks. The large stadiums have enabled both cities to host major events and international games.

Seattle has hosted multiple U.S. Men's and Women's National Team games in recent years and CenturyLink Field was a venue for the Copa America Centenario in 2016. Last year, Seattle and Atlanta were both named as host city candidates for the the 2026 FIFA World Cup as well. The large venues can also support other events, such as major concerts.

Portland has hosted international games in the past, including two matches in the 2013 CONCACAF Gold Cup. But the city has been passed over for international matches in recent years.

The Timbers won't have any trouble filling a 25,000-seat stadium and could likely sustain a much larger venue with their dedicated fan support. But the design of Providence Park and its proximity to the Multnomah Athletic Club has limited Portland's ability to add more than 4,000 seats to the stadium through expansion.

Still, the Timbers organization has said it's committed to Providence Park for the long-term.

With an additional 4,000 seats, the Timbers will still lag behind Atlanta and Seattle in attendance, but will also immediately become one of the best attended teams in MLS.

Providence Park's downtown location and proximity to public transportation also make it ideal for the Timbers. If the club wanted to find a bigger stadium, it would need to leave downtown and maybe even move to a suburb, which could negatively impact Portland's attendance and destroy the ambiance that is characteristic of Timbers games. It is also unclear what would become of the Providence Park without the Timbers. The Thorns, who are owned by the Timbers organization, and Portland State University football are currently the only other tenants for the stadium.

What do you think? Is Providence Park a viable long-term home for the Timbers? Will the club's stadium expansion project add enough seats to Providence Park? Vote in our poll and let us know your thoughts in the comments section.

-- Jamie Goldberg | jgoldberg@oregonian.com

503-853-3761 | @jamiebgoldberg