Ah, there's nothing like some running back uncertainty to stress out fantasy football players.

Will Arian Foster make his season debut following a groin injury? How about DeMarco Murray, who sat out last week with a hamstring issue? What's Marshawn Lynch's status? And will underperforming high picks C.J. Anderson and Jeremy Hill break out or continue to find themselves in growing timeshares?

Foster's situation is the most interesting among those Week 4 storylines. He's been practicing ahead of Houston's trip to Atlanta and coach Bill O'Brien said earlier this week that ''I think we're close'' to Foster's return.

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Whenever that happens, players who gulped down their nerves in August and drafted Foster in Round 6 or 7 (or maybe lower) could get a monster return on that investment. And if that team has an already-strong lineup - imagine a healthy Foster joining, say, Rob Gronkowski and Julio Jones - Foster's return could single-handedly swing your league's title chase.

If you have Foster stashed, well, pat yourself on the back and keep a close watch on Sunday's inactives list.

THE OTHER QUESTION MARKS

- It's unclear whether Murray will play for Philadelphia at Washington. If he returns, he'll try to reverse his early struggles while fitting in a crowded backfield with Ryan Mathews (24 carries for 108 yards last week) and Darren Sproles.

- Anderson left last week's win briefly with an injury and finished with just eight carries to backup Ronnie Hillman's seven. But Denver coach Gary Kubiak is committed to jumpstarting the ground game against Minnesota and says the Broncos need to keep Anderson ''on the field consistently,'' so he should keep getting chances for now.

- Two fumbles in Week 2 gave Hill a comfy spot on the sideline to watch Gio Bernard's big day for Cincinnati, then Week 3 saw Bernard get 13 carries to Hill's 12. With Bernard getting passing work, Hill's value might depend on whether the Bengals can get out in front of Kansas City. The upside is still there, so stick with him and hope for a positive sign.

- Seattle's Marshawn Lynch is uncertain to play Monday against Detroit with an injured hamstring.

HURRICANE WARNING?

Will Hurricane Joaquin affect the Eagles-Redskins game?

The National Hurricane Center's advisory Thursday night had the storm tracking further east and into the Atlantic compared to some earlier models. With showers predicted for Sunday, AP Pro Football Writer Howard Fendrich reports that conditions could affect both play-calling and ball security for both teams, with Redskins coach Jay Gruden having his running backs handling wet footballs in drills.

Poor conditions could mean a downtick in passing production, dampening the value of receivers like the Eagles' Jordan Matthews and the Redskins' Pierre Garcon, and Washington tight end Jordan Reed. It could also mean more rushing attempts for the Eagles' trio of backs or the Alfred Morris-Matt Jones duo in Washington.

LAST-MINUTE PLAYS

- If somehow Buffalo running back Karlos Williams is available in your league, grab him. With starter LeSean McCoy out (hamstring), the rookie could have a starring role Sunday against the New York Giants after scoring a touchdown in three straight games.

- Another in the grab-him-if-you-can category, Miami receiver Rishard Matthews is now owned in 67 percent of Yahoo leagues after two straight 100-yard games entering a tough matchup with the New York Jets.

- If you're desperate for receiver help, Carolina's Ted Ginn Jr. (26 percent owned in Yahoo) has 15 targets in the last two weeks heading into Tampa Bay.

- Green Bay's Ty Montgomery (7 percent owned in ESPN), who could be in line for a bigger role at San Francisco with Davante Adams hobbled by an ankle injury. And any receiver playing significant snaps with Aaron Rodgers is worth considering.

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Aaron Beard is an Associated Press sports writer based in Raleigh, North Carolina. He's in his 14th season of obsessing over lineup decisions in fantasy football. Follow him on Twitter at http://www.twitter.com/aaronbeardap and the AP's NFL site at http://pro32.ap.org .