Purdue coach Jeff Brohm may need to use his backup plan Saturday against TCU.
Brohm said starting quarterback Elijah Sindelar has been diagnosed with a concussion. Sindelar went to the team's medical tent Saturday after the Boilermakers' final offensive play, his 7-yard run on third-and-14 during a 42-24 victory over Vanderbilt.
"I think it was a concussion, a slight concussion that we'll monitor and see how he passes all the tests and go through the proper protocol," Brohm said Monday. "Hopefully, we'll get him back if he's ready to go."
Sindelar has played through pain. He tore the anterior cruciate ligament in his left knee during the first half of a 2017 game against Northwestern. Sindelar finished the game, led the Boilermakers to wins each of the next two weeks to become bowl-eligible and then was selected the Foster Farms Bowl offensive MVP in a victory over Arizona.
After having offseason surgery, Sindelar beat out David Blough for the starting job last year but made only one start and appeared in only two games because of lingering soreness in the knee.
Sindelar must go through the concussion protocol before team doctors allow him back on the field. Through two games, Sindelar has completed 68 of 104 passes with nine touchdowns and three interceptions. He leads the nation with 932 yards passing and has 11 carries for 36 yards.
On Monday, the Big Ten named Sindelar its offensive player of the week after he was 34 of 52 with a career high 509 yards, a career best five touchdown passes and one rushing touchdown.
If he can't play, redshirt freshman Jack Plummer would start.
"We're very confident in Jack," Brohm said. "He's had good weeks of practice. He's improved. He's got some moxie to him, some athleticism. I think he's gaining confidence because he's practiced well, and he has to always be ready to go. We tell him that all the time."
Plummer (no relation to former NFL quarterback Jake Plummer) came to Purdue as a highly-touted recruited from Arizona but has not yet thrown a college pass.
Sophomores Nick Sipe and Aidan O'Connell would be next on the depth chart. Sipe, the nephew of former Cleveland Browns quarterback Brian Sipe. has been slowed by a back injury since spring practice. O'Connell joined the team as a walk-on in 2017.
Whoever starts will face a Horned Frogs' defense that usually ranks among the nation's best and will have had two weeks of preparations. TCU (1-0) had a bye last week.
Sindelar isn't the only Purdue starter hurting. Brohm said he is most concerned about starting right guard Matt McCann, one of two returning starters on an already young offensive line. Sophomores DJ Washington and Mark Stickford are listed next on the depth chart. McCann will undergo more tests on his injured ankle this week. The Boilermakers (1-1) also are likely to continue to be without defensive lineman Lorenzo Neal (knee surgery) or running backs Richie Worship (knee surgery) and Tario Fuller (fractured jaw).
Brohm expects Purdue to be ready for whatever TCU throws at it — with or without Sindelar.
"Elijah has done a very good job, but like every position, especially quarterback, they're one hit from their time being up, and they've got to make sure they're ready when their number is called," Brohm said. "He (Plummer) is very smart, very cerebral. If anything, he's got some David Blough in him."