The Portland Timbers are having a tremendous season. After upsetting FC Dallas in the knockout round of the playoffs and ousting the Seattle Sounders in the Western Conference semifinals, the Timbers are now vying with Sporting Kansas City for a spot in the 2018 MLS Cup.

That’s great for Timbers fans, but it’s not ideal for construction at Providence Park.

The Timbers began construction on a $70 million-plus stadium expansion project to add 4,000 seats to Providence Park shortly after Thanksgiving in 2017. As of October, they were on track to finish construction by Spring 2019. But Portland’s deep run in the 2018 MLS Cup Playoffs forced the club to delay certain facets of its construction plan. Had Portland missed playoffs, the club would have stopped competing at Providence Park in October. Instead, the Timbers didn’t play their final home game of the season until Sunday.

Timbers President of Business Mike Golub said Monday that the playoff run has slightly impacted the timeline around stadium expansion. He said the club now expects the expansion project to be completed by late May or early June 2019.

Due to the new timeline, Golub said that the Timbers and Portland Thorns would both be on the road for a significant amount of time at the start of their 2019 seasons. Golub said that the Timbers could play their first 12 games of the 2019 MLS season on the road.

“The playoff run that we’re on -- which has been terrific for all of us and our fans -- has had some implications for the timeline of the project,” Golub said. “It has impacted the schedule of the construction completion. At this point, we’re looking at a late May, early June reopening of Providence Park.”

Less than 24 hours after the Timbers faced Sporting Kansas City in their final home game of the season Sunday, crews were busy at work at Providence Park as they prepared for the next phase of construction. By midday, cones and platforms had been set up on the field at Providence Park, an area that was unaccessible to construction crews during the season.

On Monday, the crews began disassembling the current roof on the east side of Providence Park. In the coming days, additional cranes will be brought in, so that the work on the roof can continue. The roof will be fully removed within the next few weeks, Golub said. The new roof will then be installed in parts starting in the middle or the end of December. The club will install essentially what are trays for the new seats in early January. The actual seats will be installed in early spring, Golub said.

“We knew there was a phase of work that could only begin once we knew we had no more home games this season," Golub said. "Last night was the first leg of the Western Conference Championship and that was our last game here at Providence Park for the season. Today, commences a whole bunch of work that we’ve been anxious to begin.”

Along with adding 4,000 seats to Providence Park and completely remodeling the east side of the stadium, the Timbers and Thorns also plan to add a new scoreboard and video board to the stadium in the offseason. The club will also install new turf ahead of the 2019 season. Golub said the concourse and concession stands on the west side of the stadium will be redone as well and a new team store will be built inside the stadium.

“For fans, hang in there," Golub said. "We think it will be well worth the wait. Before you know it, we’re going to be reopening Providence Park.”

According to Golub, tickets for the majority of the new seats have already been sold. Roughly 3,500 of the 4,000 new seats have been allotted to season tickets holders from the club’s season ticket waitlist. A few hundred of the new seats are also being set aside for group seating, Golub said.

Providence Park is expected to have a capacity of just over 25,000 when it reopens in 2019.

“We are looking at this as a grand reopening of Providence Park," Golub said. "In addition to the 4,000 seats and a whole new side, there are going to be changes throughout the stadium. A new team store is going in, a new video board. There will be changes everywhere. Every fan who comes in to the stadium, whether they are sitting in the new seats or the existing seats, will see exciting new changes.”

-- Jamie Goldberg | jgoldberg@oregonian.com

503-853-3761 | @jamiebgoldberg