But you can start Conner with confidence. The Pittsburgh Steelers certainly will.
ESPN Steelers reporter Jeremy Fowler thinks the second-year pro is a definite fantasy option in Week 1 ahead of running backs in timeshares such as Derrick Henry or Carlos Hyde -- despite having just 144 career rushing yards under his belt.
Fowler said Steelers backup Stevan Ridley should get some carries, but Conner will be the main guy -- and the Steelers' offensive line will be determined to make sure he goes off after some of them had harsh comments about Bell's contract holdout this week.
"We've got a little something to prove. We have to show we can do it without him," Steelers guard David DeCastro said. "If we don't do well against Cleveland, all these questions come up. ... That's why you have to do well, to eliminate those questions."
Fowler had a great breakdown on what to expect from Pittsburgh's offense without Bell -- from the running backs to the receivers and tight ends. He also wrote about the Steelers' confidence in Conner, who ran 19 times for 100 yards and caught seven passes for 61 yards in the preseason.
When Steelers coach Mike Tomlin was asked why he feels better about Bell's absence this season compared to last, he replied with one word: "James."
As for some other guys you might be wavering on as you set your Week 1 lineups, here's the intel from ESPN's NFL Nation reporters:
WR Josh Gordon: ESPN Cleveland Browns reporter Pat McManamon thinks Gordon is "definitely worth a flier" for fantasy purposes, even though the Browns have suggested he won't be a starter in Week 1. McManamon's biggest concern is actually that weather reports are calling for some possibly nasty conditions in Cleveland on Sunday, which could turn the Steelers-Browns into more of a ground game (see: Conner, above).
The idea of Gordon being rusty after missing much of the preseason is less of a concern. Last season, when Gordon returned from a three-year absence because of suspensions and addiction issues, he was immediately targeted 13 times in his first game back. He caught "only" four passes for 85 yards in that game, but that was mostly because of inaccurate throws. And the Browns have continued to express faith in him this season.
McManamon has stressed the Browns are starving to win this home opener on the heels of their 0-16 season. And Cleveland offensive coordinator Todd Haley made no secret about Gordon's ability to help them do that.
"I hope he's involved a lot. He obviously is a big-time talent. As I told him, 'We've been waiting on you. It's time,'" Haley said. "This is one of those five-star matchups. Our best players have to play better than their best players for us to have a chance to come out on top, and he's one of our best players."
RB Adrian Peterson: It's also fair to be skeptical about whether Peterson can be close to peak form in Week 1 at the age of 33, since he just signed with the Washington Redskins less than three weeks ago. But ESPN Redskins reporter John Keim said there won't be any lack of motivation or work ethic on Peterson's part -- and there won't be any lack of confidence on the Redskins' part after what they've seen so far.
"He is very competitive," Washington running backs coach Randy Jordan said. "You don't get to where he is in terms of his career if you don't have something different about you."
Keim wrote that Redskins coach Jay Gruden joked Peterson would "ideally" get about 40 carries, since that would signal the game flow was working in their favor. Peterson said that when coaches ask him how many carries he wants, he tells them, "How many times do you want? You want 30? You want 15? You want 40? Whatever it takes."
RB Dalvin Cook: If you drafted the Minnesota Vikings' dynamic second-year back, you're almost certainly going to use him in Week 1. But we still don't know if the Vikings will have any restrictions on him as he returns from last year's ACL tear.
Even the Vikings themselves don't seem to have a rigid pitch count in mind. "We're not sure yet. We're going to see how it goes," new offensive coordinator John DeFilippo said, adding that there have been no indications that Cook needs a reduced workload. "[But] if there's something that during the game that comes up where he needs to come out of the game, then we'll handle that situation."
ESPN Vikings reporter Courtney Cronin said DeFilippo's answer should offer even more confidence in Cook playing a significant role -- though no one should expect him to approach the 18.5 rushes he averaged in the first four games last season.
The other looming threat to Cook's workload is veteran backup RB Latavius Murray, who has been a great red zone option in the past. But Cronin said it's possible the Vikings will find ways to get both of them on the field at the same time in DeFilippo's creative offense. She pointed out that Murray was actually working out with the receivers during Friday's practice.
RB Royce Freeman: You should have no qualms about starting the Denver Broncos rookie in Week 1. But the question with Freeman is how quickly he can assume the true leading-man role that the Broncos envision for him. ESPN Broncos reporter Jeff Legwold broke down his chances of being "an every-down back and fantasy threat" for a team that hasn't had a running back top 250 carries in 14 years. "Ultimately, the Broncos seem inclined to give him as much work as he can handle," Legwold wrote.
On the plus side, Broncos coach Vance Joseph complimented Freeman's ability to handle such a role from both a physical and mental standpoint -- and said he is "really good" in pass protection. But Joseph also said Devontae Booker will continue to be used on third downs and fellow rookie Phillip Lindsay will have a role, as well.
TE Antonio Gates: The Los Angeles Chargers haven't even made it official yet that the 38-year-old will play after just re-signing him this week. But ESPN Chargers reporter Eric D. Williams said Gates looked "surprisingly quick and polished" while running routes in practice, considering how much time he missed. "Those fresh legs could come in handy if he's active on Sunday," Williams said.
Patriots: The New England Patriots' backfield probably will never be easy to sort out for fantasy purposes. But ESPN Patriots reporter Mike Reiss offered up some educated guesses on roles for Week 1. He believes newly elected captain James White should see plenty of snaps as a runner/receiver after playing 43 of them in last year's season opener. He expects Jeremy Hill to serve as the power back. And he estimates about 20 to 25 snaps for Rex Burkhead, as he is still being eased back into the mix from a knee injury. Meanwhile, Reiss said he wouldn't be surprised if rookie first-round draft pick Sony Michel is inactive in Week 1 after being limited in practice this week with a knee issue.
Cowboys: Health issues along the offensive line and departures at wide receiver and tight end might have lowered expectations for Dallas Cowboys running back Ezekiel Elliott. But ESPN Cowboys reporter Todd Archer wrote that Elliott is rested, fresh and ready to prove he is the "best back" in the NFL.
Giants: ESPN New York Giants reporter Jordan Ranaan wrote that rookie Saquon Barkley's NFL debut should include plenty of touches. ... Ranaan, Jacksonville Jaguars reporter Michael DiRocco and the rest of ESPN's staff wrote lots of great stuff about the tantalizing matchup between Giants receiver Odell Beckham Jr. and Jaguars cornerback Jalen Ramsey. ... Also worth noting: Giants TE Evan Engram is out of the concussion protocol and set to play in Week 1.
Ravens: Your fantasy team might not have enough shares in the Baltimore Ravens' offense. ESPN Ravens reporter Jamison Hensley wrote about how they might be a "breakout" unit this year with QB Joe Flacco healthier, RB Alex Collins on the rise and the WR group much more loaded.
Colts: Quarterback Andrew Luck's return from a major shoulder injury has been impressive throughout the summer. ESPN Indianapolis Colts reporter Mike Wells wrote that Week 1 will be his "final hurdle."
Saints: I've been preaching caution with fantasy expectations for both New Orleans Saints receiver Cameron Meredith and running back Mike Gillislee as ESPN's Saints reporter. Although Meredith finally had a breakout performance last week with his first two catches of the preseason for 72 yards and a touchdown, he is still working his way into the Saints' mix after missing time this offseason. It wouldn't be a shock to see Meredith inactive in Week 1, since the Saints kept fellow slot receiver Austin Carr on their active roster. Gillislee, meanwhile, could see some goal-line work behind starter Alvin Kamara. But I'm not expecting a big role after he just joined the team on Sunday. And I expect the Saints to activate a third running back this weekend (most likely Jonathan Williams).
Dolphins: Speaking of Kamara, ESPN Miami Dolphins reporter Cameron Wolfe wrote about Sunday's matchup between "Bama buddies" Kenyan Drake and Derrick Henry -- two young running backs set to take on leading roles for the Dolphins and Tennessee Titans, respectively. Kamara was part of that same loaded Alabama backfield in college before he decided to transfer and ultimately wound up at Tennessee.
Panthers: Now that Carolina Panthers quarterback Cam Newton has been paired with accomplished offensive coordinator Norv Turner, ESPN Panthers reporter David Newton wrote about what might be in store for the next chapter of Cam's career.
Cardinals: Not only is Arizona Cardinals running back David Johnson back healthy and ready for a resurgence after last season's wrist fracture, but ESPN Cardinals reporter Josh Weinfuss also wrote about how much better Johnson feels now that he has ditched the vegan diet.