The Tampa Bay Buccaneers finished off their latest training camp workout Wednesday in typical fashion by running a simulated two-minute drill.

The difference this time was at right defensive end where rookie Steven Means played in place of starter Adrian Clayborn. The change was not by design.

Clayborn the 2011 first-round draft pick who missed all but three games last season after tearing ligaments in his right knee injured a groin and was not able to finish Wednesday's practice. The severity of the injury was not immediately revealed by the Bucs who are relying on Clayborn to improve a pass rush that finished tied for 30th in the 32-team league with 27 sacks last year.

“He couldn't practice the rest of the day and that's usually not a good sign'' Bucs coach Greg Schiano said. “After the individual workouts he was done and everybody else bumped up a spot. That's why (Means) was out there.''

Clayborn who has not been as limited in camp workouts as other players coming off season-ending injuries was not available for comment.

“Adrian is incredibly frustrated obviously after being out all that time last year with the surgery and now he just gets it rolling again and something else holds him back'' Schiano said. “But that's the way life goes.''

Life without Clayborn who led Tampa Bay with 7.5 sacks as a rookie in 2011 could prove devastating for a team that has not cracked the 30-sack mark in a season since recording 33 in 2007.

The team allowed 2012 sack leader Michael Bennett to leave for Seattle in free agency in the spring so it is left with mostly young and inexperienced players such as Means in reserve roles along the defensive front. Daniel Te'O-Nesheim a fourth-year pro who earned high praise from Schiano after producing four sacks as Clayborn's replacement last year is the exception.

Still Schiano admitted there is a dropoff between first- and second-teamers.

“Like I've always said the No. 1 players are the No. 1 players for a reason'' Schiano said. “The next guy is usually not as good or he would be the No. 1 guy.''

In at least one case up front the Bucs still aren't sure if their No. 1 guy is worthy. That's at left end where third-year pro Da'Quan Bowers has replaced Bennett. The Bucs think Bowers is ready to make an impact as an edge rusher and run stopper but his play through the first week of training camp has not necessarily been up to their standards.