Notre Dame star quarterback Riley Leonard returned in the third quarter of the Orange Bowl on Thursday after entering concussion protocol late the first half following a big hit. Leonard's brief absence injected some uncertainty for the 7-seed Fighting Irish in their College Football Playoff semifinal battle with 6-seed Penn State.

Notre Dame quarterback Riley Leonard was ushered off the field by officials after a possible concussion in the Orange Bowl against Penn State, but returned.

Notre Dame heads to halftime down 10-3 against Penn State and perhaps without its starting quarterback for the second half

No. 7 seed Notre Dame and No. 6 seed Penn State are set to revive their rivalry in the Orange Bowl on Thursday evening with a spot in the College Football Playoff National Championship on the line. This will be the first meeting between two storied programs since 2007 and just the 20th all time.

Notre Dame QB Riley Leonard suffered an injury vs. Penn State in College Football Playoff semifinal at the Orange Bowl.

Notre Dame quarterback Riley Leonard left the game with an injury, while Penn State's run game is dominating.

Notre Dame vs. Penn State in CFP Semifinal Orange Bowl at Hard Rock Stadium. Follow along for live scoring updates

Win and you’re in. No. 6 Penn State and No. 7 Notre Dame battle it out in the Orange Bowl at Hard Rock Stadium for a spot in the National Championship Game. Kickoff is 7:30 p.m. ET on Thursday, Jan. 9 on ESPN.

Follow the action live as the Fighting Irish and Nittany Lions face off in south Florida with a spot in the College Football Playoff title game on the line.