Last year during this week he was at Tulsa (Okla.) Booker T. Washington preparing to play Stillwater (Okla.) High. He wasn't attending the annual Red River Rivalry showdown between OU and Texas.
Instead he was making yet another unofficial visit to Arkansas, the school he had committed to four months prior.
Alexander grew up an OU fan, but the Sooners weren't quick to offer. Following an impressive camp showing in June 2012, he was told to wait. More evaluation was needed before the Sooners would take that next step.
So while OU was running wild on the Longhorns, Alexander was in Fayetteville. This year Alexander is potentially going to be the starting linebacker when OU and Texas meet Saturday morning.
"There are a lot of expectations coming out of me," Alexander said. "I've just got to play a lot better. Corey (Nelson) is right there with me so he's helping me out the whole way through, knowing what I need to know and everything."
Alexander is being thrust into the spotlight because of an injury to senior captain Corey Nelson. He suffered a partially torn pectoral muscle during the third quarter of last week's victory.
It's not like Alexander has been a stranger to the OU defense. He has played a lot through the first five games, alternating with Julian Wilson on defensive packages. On perceived run downs, Alexander has been in. When it's looked like passing situations, Wilson returns.
There won't be any alternating this time around. It's Alexander's show, and he got a taste of that in the fourth quarter last week.
"I learned that I've got to play faster," Alexander said. "I can't get caught up by guards. Everything was just a learning experience. Guys are a lot faster, bigger and stronger so all I can do is just learn from it and get better."
Alexander was a firm Razorbacks commit until OU entered the picture. The Sooners offered Alexander in October, a week before OU's game with Notre Dame.
Following an incredible unofficial visit, Alexander quickly flipped his commitment from Arkansas to OU. But the struggle wasn't done just yet. Alexander promised Arkansas that once it found a new coach, he would reevaluate things.
Enter Bret Bielema, and the Razorbacks did all they could. Enter Kansas State, and the Wildcats did all they could.
January was an interesting month for Alexander, who took official visits to both schools before ultimately sticking with the Sooners.
There were no guarantees about a starting spot or anything like that, but OU defensive coordinator Mike Stoops had a feeling Alexander might be ready sooner rather than later.
"Dominique is going to be a great player," Stoops said. "He is the next guy up, and he has to go play. He's very well prepared for this, and I think he is going to be an unbelievable player. Hopefully it's Saturday. We'll see, but he'll be well prepared, and he'll hold his own. I can guarantee that."
It won't be an easy task for Alexander, who has 10 tackles this season. Nelson was having a banner start to his senior season, a real leader on and off the field.
His play on the field will be missed. There's no doubt about that. But his presence on the sidelines and his composure might be missed even more.
Nelson is trying to help Alexander in any way he can.
"He has been like my big brother," Alexander said. "As soon as I got here, he took care of me. He's just telling me I have to step up in a significant way. This is Texas week, and I can't let the crowd get to me.
"He's keeping me in the film room with him He's make sure that I'm really going to be on my stuff, and I'm not going to have any busts. He's going to make sure I'm the best player I can be."
OU will certainly need Alexander at his best Saturday.