"I tell these guys all the time, ‘I don't know if there's such a thing as a backup. You have to be ready,' " Johnson said.
After all, a starting job may always be a play – or a suspension away.
That was the case for Clarke. When Ohio State announced two days before last Saturday's opener that the No. 1 cornerback, Travis Howard, was suspended for the game against Akron because of an NCAA violation, Clarke was pressed back into the starting role he thought he had lost during camp.
The Maryland native responded with a dominating day, breaking up the key passes that came his way and tipping one throw into the air for linebacker Andrew Sweat to pick off. When it came to following his coach's mantra of being ready to play, Clarke did it to a T.
"I feel like in practice, I try to go with the mentality of, I don't ever feel like there's not a chance (that I'll play)," he said. "Anybody can play. I go out there and try to compete (in practice) so if anything does happen – I feel like all of us are always ready."
Count Johnson among those impressed.
"He was ready," Johnson said. "He stepped right in in the very first game."
For the day, Clarke finished with four solo tackles and two pass breakups in his first career start, but he wasn't credited with a pass breakup on his biggest play of the game, the ball he tipped for Sweat to corral.
With Ohio State up 14-0 and the first half clock ticking down, Clarke had excellent position on a pass from Clayton Moore to Jarrod Dillard, knocking the ball into the air.
But the play wasn't over for Clarke at that point. As Sweat flew into the picture to intercept the pass, the cornerback made sure his teammate would be able to come up with the ball.
"I was going down and I thought he was trying to get it, so I was pulling the receivers' hands down, so I didn't get it," he said. "I saw Sweat jump in the air and get it. … I was glad my teammate was there to pick it off for me."
As one would expect from a senior leader who benefited from the play of a sophomore, Sweat was effusive in his praise of Clarke afterward.
"Dom competes every day," Sweat said. "I think he's a great player. In the Sugar Bowl, I don't know if he was expecting to play but he got thrust into that position. He did a good job. I think that he can only build on that experience. He got an opportunity Saturday and took advantage of it."
As Sweat alluded to, Clarke was thrust into the limelight a year ago in the Buckeyes' Sugar Bowl victory against Arkansas. When starter Chimdi Chekwa went down with a wrist injury against the Razorbacks, Clarke – who had 11 tackles and his first career pick up to that point on the year – was pressed into action and made three tackles on the day.
It shouldn't be a huge surprise that Clarke is able to step up on the big stage, however, as the 5-10, 191-pounder carries a fair bit of swagger on him.
"I was like, ‘Hey, it's time to go out there and show everybody I can play,' " he said of his Sugar Bowl experience. "That right there got everything rolling, I feel like."
Comments like those out of his defensive backs are music to Johnson's ears.
"When you play a secondary position especially, you have to have some of that confidence internally before you get here," Johnson said. "You have to understand that when people get to this level, people are going to come after you. The expectations are through the roof when you play here."
It was easy to see confidence is no issue for Clarke as he beamed smiles in the postgame interview room at Ohio Stadium after the Akron game, but his next challenge becomes staying on the field.
Johnson wouldn't commit to Howard starting on Saturday vs. Toledo but said the junior from Florida will play, leaving Clarke's status uncertain. The sophomore was hopeful he'll get another nod; if not, he'll be ready to go again when called upon.
"As a player, I want to play," he said. "So does everybody else out there. We'll listen to the coaches. I hope they saw (what I did), you know what I mean?"