The Minnesota Vikings kicked off their season like a house on fire, beating the New Orleans Saints in Week 1, 29-19. However, the biggest player in that win is battling uncertainty in regards to his availability for this coming Sunday’s road game against the Pittsburgh Steelers. Quarterback Sam Bradford, who had his knee examined after facing the Saints, is considered questionable for the game, according to sources of ESPN’s Chris Mortensen.

Bradford on Tuesday had an MRI on the knee after another source told ESPN that the quarterback had experienced swelling, pain and discomfort following Monday night's victory over the New Orleans Saints.

This is a concerning development for the Vikings, who saw Bradford pass for 346 yards and three touchdowns without an interception on 27-of-32 attempts in the Saints game. While it’s good news for Bradford that no structural damage was found in his knee after having an MRI, that doesn’t necessarily mean he’s clear of any health issues.

The source said the MRI did not reveal any specific damage, but those scans do not always offer a clear picture in a knee that has undergone multiple ACL repairs. It is the same knee that underwent ACL repairs in 2013 and 2014, when Bradford was with the Rams.

Until an official announcement by the team is made, though, it should be assumed that Bradford will be taking snaps under center at Heinz Field.

Bradford has been listed as a limited participant on the team's practice reports all week, but the source said the thought was that Bradford would be able to play when the Vikings visit the Pittsburgh Steelers on Sunday.

Bradford has had numerous injuries before so it wouldn’t also be much of a surprise if the Vikings decide to put him on the shelf for at least Week 2. In that case, backup Case Keenum will take over the starting quarterback duties this Sunday. Keenum is coming off a season in which he passed for 2,201 yards and nine touchdowns with 11 interceptions for Bradford’s former team, the Los Angeles Rams.