CINCINNATI — Clinton Portis didn’t even want to be on the field for the first preseason game. Now, the dependable running back isn’t sure if he can be on the field when it counts.

The Washington Redskins’ revamped offense took a significant jolt Sunday night when Portis partially dislocated his left shoulder during a 19-3 loss to the Cincinnati Bengals, leaving him sidelined indefinitely.

‘‘Right now, it’s tough to say,’’ coach Joe Gibbs said. ‘‘Obviously, it’s going to be a while.’’

Portis ran for a club-record 1,516 yards last season, when Washington made the playoffs as a wild-card team, and was counted on to steady an offense retooled by assistant coach Al Saunders in the offseason.

Instead, Washington is wondering how long it will be without its best running back — something Portis can’t comprehend.

Portis opened the game with an 8-yard carry, then blocked for Mark Brunell’s passes. When Brunell’s sixth throw was intercepted by cornerback Keiwan Ratliff, Portis ran him down and reached to make the tackle.

His left arm was extended when he hit Ratliff, momentarily knocking the bone part of the way out of the shoulder socket. An MRI confirmed the injury.

‘‘After that 8-yard run, I was like, ‘Get me out of that game,’’’ Portis said. ‘‘That’s what I was thinking. It’s football. It can happen to anyone. It happened to me.’’

Standard treatment involves rest and strengthening exercises. Portis had the left arm in a blue sling after the game, when he lobbied for regulars to play less in the preseason.

‘‘For whoever’s watching: Let’s get rid of some of these games,’’ Portis said. ‘‘Four games is ridiculous. Then you play a 16-game season and the playoffs behind that.’’

Gibbs planned to keep Portis and his other starters in the game for only a short time.

‘‘We wanted to have one good drive,’’ Gibbs said. ‘‘We didn’t want him to carry the ball more than one or two times.’’

Without Portis, the running game will depend upon backup Ladell Betts, who ran for 338 yards last season and missed four games because of a knee injury.

‘‘Who knows what it is?’’ Portis said of his injury. ‘‘Even if it’s not serious, to be nicked up for the first week of the season …’’

For Cincinnati, the opener was a chance to gauge what the offense will look like if Carson Palmer isn’t ready to start the season. Palmer stood on the sideline in a white Bengals T-shirt and gray sweat pants, watching newcomer Anthony Wright make a lackluster debut.

The Bengals failed to get a first down on their first three series behind Wright, a free-agent quarterback signed less than four months ago. He was sacked twice and looked indecisive in those three drives.

He finally got going with the help of a flea-flicker — a trick play seldom used in preseason — that surprised the Redskins. T.J. Houshmandzadeh was unguarded downfield for a 52-yard catch, setting up Wright’s 12-yard touchdown pass to Chris Henry.

‘‘I think overall it was a good start, for the first time,’’ Wright said. ‘‘There’s a lot of complications to this offense.’’

Wright was 9-of-16 in the first half for 101 yards, more than half of them on the one trick play. Doug Johnson went 11-of-14 for 128 yards with a touchdown and three sacks in the second half, when both teams played their backups.

Palmer tore ligaments in his left knee during a playoff loss to Pittsburgh in January and had reconstructive surgery. He’s not expected to play until at least the third preseason game, leaving his status unclear.

Bengals Pro Bowl receiver Chad Johnson showed up with a new look — his mohawk was dyed blond — but didn’t catch a pass in limited action. Johnson had shaved his head for games in the past.

Henry, one of six Bengals either arrested or suspended in recent months, had six catches for 61 yards. He is scheduled to go on trial on a gun charge in Florida later this month.

Brunell played only two series, going 4-of-9 for 66 yards with the interception by Ratliff that was Portis’ final play. Backup Todd Collins finished the first half, going 6-of-13 for 68 yards with an interception. Collins also was called for intentional grounding in the end zone, resulting in a safety.

Notes: Redskins second-string LB Chris Clemons sprained a ligament in his left knee late in the first quarter. Trainers put a brace on the knee before he was helped off without putting weight on the leg. … RB Kerry Carter had to be helped off the field with an injured right knee in the second quarter. The Redskins signed Carter as a free agent in January after he missed last season. … WR Mike Espy, an undrafted free agent from Mississippi who is the son of former Agriculture Secretary Michael Espy, caught four passes for 56 yards for Washington. … The crowd of 64,961 was the largest for a preseason game in Paul Brown Stadium’s seven years.