LATROBE, Pa. – It took a little longer than anticipated, but Mike Mitchell has finally begun to deliver as advertised.

The veteran safety who was the crown jewel of the Steelers' offseason additions filled the hole and dropped running back Le'Veon Bell for a short gain on the first play of the first 11-on-11 tackling drill on Monday. It was Mitchell's first appearance in a training camp practice after being activated from the physically unable to perform list earlier in the day.

Later, Mitchell closed fast in a red zone drill and knocked a pass away from wide receiver Markus Wheaton at the goal line. After doing so Mitchell reacted as if he felt he should have intercepted the ball.

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"We expect him to come in and make plays and be a strong tackler, and he's living up to that," defensive backs coach Carnell Lake assessed. "For the time he's missed he looked sharp (on Monday). He got a little tired towards the end of practice so we decided to give him a rest, make sure he didn't have any setbacks.

"But I liked what I saw today."

Lake also likes what he sees from a secondary that was part of a defense that at times hemorrhaged big plays last season.

The numbers told an agonizing tale: The Steelers surrendered 11 plays of 51 or more yards and 17 that gained at least 40 yards while in the process of finishing ninth in pass defense, 21st in rushing defense and 13th in total defense in 2013.

They hadn't finished as low as 13th in total defense since 1992, Bill Cowher's first season as coach, when Lake was a starting safety. Lake, among others, wasn't pleased with last year's performance.

"My first two years here we were first in pass defense," he said. "Last year we were ninth in pass defense. We weren't happy with ninth, not the way we set the standard around here. One of the reasons why we were ninth is we gave up more big plays than we had in the past, and I think those are easily correctable. The second half of last year we got those corrected.

"I think we all know going into this camp what's expected, and we're going to be conscious of that and then we're going to see if we can get the turnovers going. The only things that we've really been missing the last three years are the turnovers. But the first and foremost objective of the secondary is to prevent the ball from going over our head and to give our offense a chance. We're very capable of that."

The Steelers took the ball away 20 times last season (10 interceptions and 10 fumble recoveries). Only the Saints (19), Chargers (17), Jets (15) and Texans (11) had fewer takeaways. The Vikings tied the Steelers with 20.

The corrections that Lake referenced were mostly related to assignment issues, he said.

"We have to make sure we're more disciplined," Lake maintained. "We had guys last year who were probably out on the edge a little bit and it caught us a couple times. We were just out of place trying to make plays happen.

"We have to know that we're not a unit in and of ourselves. We have to work within the confines of the defense. You know, when you lose the first four games in a row guys sometimes have a tendency to try to help out in other areas. And then it can get out of hand, spiral out real quickly, because there are other breakdowns when you're not taking care of your job."

Lake is already looking forward to starting anew via Saturday night's preseason opener against the New York Football Giants.

"As bad as it seemed last year we really weren't that far off," he said. "And we got it corrected; we just didn't get it corrected in time. I'm excited for the season. I'm ready to go for Saturday when we play the Giants. I'm just ready to start playing."