FLOWERY BRANCH — The Atlanta Falcons returned from their bye week Tuesday with big holes to fill on offense.

Running back Steven Jackson was only an observer and wide receiver Roddy White and left tackle Sam Baker were not on the field for the portion of the practice open to reporters.

White, already slowed by a right ankle sprain, left the Falcons' 30-28 loss to the New York Jets on Oct. 7 with a hamstring injury. Leading receiver Julio Jones hurt his right foot in the game and will miss the remainder of the season.

Harry Douglas, Kevin Cone and Drew Davis could be Atlanta's top three receivers against Tampa Bay on Sunday.

Brian Robiskie, who signed last week, had extra work with quarterback Matt Ryan Tuesday.

Offensive coordinator Dirk Koetter said he must tweak the offense to fit the strengths of the fill-ins.

"With Julio definitely out and Roddy may or may not be out, those are two of the best players in the NFL," Koetter said.

"Are those (backup) guys going to be as good? That's an obvious question and answer."

The injuries have added more gloom to the Falcons' 1-4 start. Atlanta will take a three-game losing streak into Sunday's game.

"We're in a difficult streak with injuries right now, but I think as coaches we look at it as a challenge," Koetter said. "No one thinks you have a chance right now, so let's try to figure out a way to get this done."

Koetter said it is a "no-brainer" that tight end Tony Gonzalez could become quarterback Matt Ryan's top target.

Gonzalez, 37, has 22 catches for 246 yards and two touchdowns the last two weeks.

If Gonzalez receives extra defensive attention from the Buccaneers, Douglas and other receivers must take advantage of one-on-one coverages.

"Those guys have to do the best they can and we've got to play to their strengths and work with the guys we have," Koetter said. "We've still got a great quarterback. We've still got a great tight end. We've still got excellent running backs. It just changes the way you attack a little bit."

Douglas has been a complement to Jones and White the last two seasons and has never been asked to be the team's No. 1 receiver. That could change this week, especially if Tampa Bay focuses its defense on Gonzalez.

"I'm the kind of player, I'm not selfish at all," Douglas said. "I'm here to do whatever I'm asked to do. If that is to be a No. 1, I've got to step up and be a No. 1. ... I don't shy away from anything."

Douglas said players have remained positive through the stretch of losses and injuries.

"We've got to do what we've got to do to stay close as a team so we can turn this thing around," Douglas said.

"You can't moan and complain. You can't point fingers. And that's one thing we do a great job of. We've owned up to the mistakes we've made in games. Now we just have to turn the ship around."

Baker missed the game against the Jets with a knee injury.

The good news for Atlanta on Tuesday was the return of running back Jason Snelling from a concussion. Snelling and Jacquizz Rodgers would continue to share time if Jackson misses his fourth straight game with a hamstring injury.

The bye week gave Snelling time to clear the NFL's concussion protocol. The Falcons worked without pads on Tuesday. Coach Mike Smith said Snelling also will be cleared for contact drills on Wednesday.

"I had to take my time to get right and go through all the protocols," Snelling said. "It felt good to be out there with my team again."

The defense is missing linebackers Akeem Dent (ankle) and Sean Weatherspoon (foot). Dent, who didn't play against the Jets, did not participate in the open portion of Tuesday's practice. Weatherspoon must miss at least five more games.

Earlier in the season, starting fullback Bradie Ewing and defensive end Kroy Biermann were placed on injured reserve.