Worilds would have had those looks due to starter James Harrison's back issues holding him out for a little bit.
Neither of those injuries appear to be long-term issues, but they seem to be happening often enough now the Steelers may want to explore some long-term depth at the position.
That's where Carter comes in.
Although he looked, frankly, lost in his limited time last season, he showed a burst off the snap that could prove useful as he continues to grow as a player. He doesn't have the size (6-foot-1, 248) Worilds (6-foot-2, 262) does, but he looked more aggressive per-snap.
Neither looked particularly great against the run, but to their credit, they are both young players still learning the defense.
And learn quickly, they must. Harrison missed four games last year, and OLB LaMarr Woodley essentially missed eight. Their lack of field time produced just 35 sacks, which was 17th in the NFL, down from the 48 they produced the previous season.
Maybe it's a shot across the bow of the younger players, but the Steelers brought in former Bengals inside/middle linebacker Brandon Johnson and moved him outside. Perhaps Johnson will serve as a lead horse to contend with Worilds and handle special teams duties, but with Worilds' surgery, if Carter is to have a chance to compete for snaps, this training camp will be his best opportunity.