When opportunity comes knocking in the NFL, it's always interesting to see which players are able to step up and to take full advantage of it.

Because of injuries and pending suspensions, the Detroit Lions are in a unique situation where one of their rookie defensive ends just might find themselves on the initial 53-man roster.

Seventh-round draft pick Pat O'Connor and undrafted free agents Alex Barrett and Jeremiah Valoaga are competing for what might end up being just one roster spot behind Ziggy Ansah, Cornelius Washington and Anthony Zettel. The Lions lost Kerry Hyder Jr. for the season with an Achilles injury, and veteran Armonty Bryant will begin the season on a four-game suspension.

"It's a big week," O'Connor said Monday. "You just have to take every opportunity like it's your last. Prepare as you always do, and when your name is called, you have to make the best of it."

All three players should see significant playing time in Thursday's preseason finale in Buffalo. It's the final piece of the evaluation process for head coach Jim Caldwell and general manager Bob Quinn before they are required to trim the roster from 88 players to 53 by 4 p.m. Saturday.

At this point, the competition appears to be too close to call.

"It's a pretty tight competition obviously which you notice and understand," head coach Jim Caldwell said. "All three guys have a certain level of expertise depending upon their size, body types, etcetera that they use to their fullest to try and make certain that they get in position to do their absolute best.

"And so this week is one where they'll get a decent amount of playing time. So, it just kind of helps. It's part of the evaluation is getting narrowed down right about now. So, we'll see what happens."

All three players have recorded one sack in the preseason. Valoaga leads the trio in tackles with nine. Barrett has seven, and O'Connor has two. O'Connor also has a fumble recovery.

Valoaga said he's not letting himself think about the gravity of this week and what Thursday's performance could potentially mean for his roster status.

"Every day is a learning experience," he said. "I'm just taking it day by day, seeing what I can do, and doing the best I can."

There are a number of interesting storylines developing for Thursday night's game, and whether or not any of these rookie edge rushers can separate themselves from the pack is right there at the top.

EBRON BACK

Tight End Eric Ebron returned to the portion of practice open to the media Monday after missing most of the last month due to injury. 

Ebron injured his hamstring the first day of training camp and hasn't taken part in a full practice since. His return to practice is a good sign he could be ready to go by the start of the regular season. He could certainly use a couple weeks of practice to knock off the rust after missing so much time.

Receiver TJ Jones was also back on the practice field after injuring his hamstring in Detroit's second preseason game vs. the Jets a couple weeks ago. So was tight end Cole Wick, who left Friday's game vs. New England with a chest injury.

Not taking part in practice Monday were: Matthew Stafford, Tahir Whitehead, T.J. Lang, Rick Wagner, Kenny Golladay, Miles Killebrew and Zach Zenner.

EXTRA BODIES

The NFL changed its rules this offseason and eliminated a round of cuts that typically came following the third preseason game. In years past, teams were required to trim the roster from 90 to 75 before the last preseason game. Teams didn't have to make that cut this year.

It means teams will have more players at their disposal for the final preseason game. The Lions currently have 88 players on their roster.

"I see there's some benefits obviously because usually going into this game particular, you are teetering on the edge of putting maybe a guy or two in the game that you wouldn't necessarily - would not like to put him in," Caldwell said.

"But what it does, is it leaves us a little more flexibility, and I think that's a plus. We have a few guys we can evaluate and I think that's one of the reasons why obviously it was put into place in terms of the rule."