The No. 5 overall pick in the draft didn't record his first official tackle until he sacked Detroit Lions quarterback Kellen Moore well into the third quarter -- that came against the Lions' third-string offense. (Mack had a first-quarter tackle wiped out by a penalty flag.)
Coach Dennis Allen said the team left the rookie in the game to get reps under his belt.
"It's numbers of plays. It's trying to get his play-count up. The only way you can get better is get experience," Allen said, noting the team had a target number of plays for Mack, per the San Jose Mercury News. "I know he was a high draft choice, but he needs to play. And that's the only way he's going to get better."
Even though he only had two tackles in each of his first two preseason games, Allen believes Mack has displayed improvement through two games.
"Well, obviously there wasn't a ton of production from the standpoint of tackles or assists or sacks or whatever the case may be," Allen said. "But I thought he made improvement from where he was at last week. We'll have plenty of more opportunities to do some different things and get him maybe a little more involved."
Part of the reason Mack had to play against third-stringers to reach his play count was that he's stuck on the sidelines in certain packages -- including, oddly, the early nickel formations on Friday. Those coaching decisions are one reason Mack's usage in Oakland is being questioned by some critics.
Mack was highly praised entering the NFL, and coaches loved his versatility early in offseason workouts. It's still very early, but unlike some other rookies, we haven't seen Mack stand out yet.