CINCINNATI -- Sean Porter admitted Monday that he was "frustrated and angry" with the numerous injuries he has collected since first donning a Cincinnati Bengals uniform in April 2013.

They are quite surprising to the outside linebacker because until this point in his entire football-playing career, he had been relatively injury-free.

He was healthy in Pop Warner. He had few injury concerns in high school. He breezed through college without missing snaps or downs at Texas A&M, appearing in 100 or so plays on both defense and special teams in certain games.

He was a workhorse. He was dependable.

In the nearly 17 months since the Bengals drafted him, Porter has been anything but. He tore the labrum in a shoulder before last season. The injury shelved him the entire 2013 season and forced him into taking it slowly before he could work himself back into football shape earlier this year. Just as he was getting to that point in training camp, Porter suffered a knee injury. After that cleared, he had another setback last Thursday when he tweaked a hamstring just six plays into the preseason finale against the Colts.

"I wanted to really be able to prove to my teammates that I'm a good player, and that I can go out there and help contribute," Porter said Monday, two days after he survived roster cuts. "I was a little disappointed I couldn't finish that game. I've just got a run of bad luck. I guess it just happens and at some point it'll even out."

When asked about his hamstring Porter simply said it was "getting there."

Apparently it's not there yet. He was one of three players on the 53-man roster sidelined with an injury when the Bengals opened regular-season practices Monday afternoon. Along with Porter, running back Rex Burkhead and receiver Marvin Jones also didn't practice. Jones, who has been wearing a boot and crutches since foot surgery three weeks ago, isn't expected back until the Bengals visit New England on Oct. 6.

Burkhead has had a knee injury since the Bengals' Week 2 preseason game against the Jets. There is no indication how bad Burkhead's injury is, but the hope had been that he'd be healthy before the season got too far along. In addition to those practice absences, the Bengals also were without quarterback AJ McCarron who was placed over the weekend on the non-football injury list. He can't practice until after Week 6. Practice-squad defensive tackle Devon Still also missed practice as he continues juggling his personal life with his returning from a hamstring injury of his own.

Still's 4-year-old daughter has stage-4 cancer.

It was worth noting that receiver James Wright, cornerback Darqueze Dennard and linebacker Vontaze Burfict were practicing after missing the last game. None of them played Thursday. Since the Bengals were practicing on what is normally a day off, they still haven't reached the date where they must file daily injury reports. So we're not sure which players were in full or limited capacity. We'll have better details Wednesday when Bengals' injury-report filings officially begin. Here's Monday's injury report:

Out

LB Sean Porter (hamstring)

RB Rex Burkhead (knee)

DT Devon Still (hamstring)

WR Marvin Jones (foot)

QB AJ McCarron (shoulder)

Returned to practice

WR James Wright (head)

CB Darqueze Dennard (hip)

LB Vontaze Burfict (hamstring)

Other notable practice additions

TE Tyler Eifert (shoulder)

OT Andre Smith (head ... has been practicing, but didn't take a preseason snap)