The Toronto Raptors will be without their starting frontcourt of Jonas Valanciunas and Serge Ibaka for their visit to the Portland Trail Blazers on Monday night.

Valanciunas has missed the last three games after suffering an ankle sprain in the Raptors’ second game of the season against the Philadelphia 76ers.

Meanwhile, the absence of Ibaka will be another big blow to the Raptors. The 28-year-old is the team’s second-leading scorer behind DeMar DeRozan this season, averaging 15 points on 54 percent shooting from the field and 39 percent on 3-pointers.

With Valanciunas and Ibaka both out, the Raptors will likely turn to second-year players Pascal Siakam and Jakob Poeltl to start.

Siakam has been incredibly productive since being inserted into the starting lineup. After putting up 20 points on 9-of-12 shooting in 21 minutes against the Golden State Warriors, he had 18 points on 8-of-10 shooting in 25 minutes against the Los Angeles Lakers.

Poeltl has been similarly effective as he’s become a regular part of the rotation this year. He’s averaging 9.0 points, 8.6 rebounds, and 1.8 blocks in 21 minutes per game.

Fourth-year big man Lucas Nogueira didn’t play in the Raptors’ most recent game against the Lakers due to an ankle injury and is also questionable to play. If he remains inactive, rookie OG Anunoby may need to play minutes as the team’s emergency backup center.