Conference tournament upsets are wreaking havoc on the margins of the NCAA Tournament ahead of Selection Sunday.

Portland swooped in to steal a bid with its upset of No. 16 Gonzaga in the West Coast Conference final, while South Florida’s loss to Wichita State in the American Athletic quarterfinals means another team from that conference will snag a spot. With Gonzaga and South Florida as clear at-large selections, the other teams on the bubble should be sweating.

Syracuse, Nebraska, Purdue and St. John’s are among the teams in the running for the last at-large berths. With conference tournaments ongoing through the weekend, here are the tournaments and the teams the bubble hopefuls need to watch.

Conference USA

Middle Tennessee State sits at No. 25 in the AP poll. The Blue Raiders (25-4) are a lock as an at-large bid if they do not win their conference’s automatic bid. They’ll start their quest for the title with a quarterfinal matchup against Charlotte at 12 p.m. ET Thursday. If they lose, that will be another space off the board for bubble teams.

Ivy League

Princeton and Columbia are both in the running for NCAA Tournament berths heading into the Ivy League tournament. If all goes to plan, the first- and second-seeded teams will meet in the championship game at 5 p.m. ET Saturday, and then both should hear their names called on Selection Sunday.

If Penn or Harvard manages an upset in Friday’s semifinal round, the loser could find themselves out of the tournament field. Or, if Princeton and Columbia manage to stay in the field of 68, that would burst another team’s bubble.

Mountain West

The Runnin’ Rebels have streaked to a 30-2 record overall and a perfect 18-0 record in the Mountain West. They have looked unstoppable against conference competition — but if they run into a wall against Wyoming in the championship game at 10 p.m. ET Wednesday, that would spell trouble for the teams vying for one of the final spots.