Gone are the days when fantasy managers could draft well, mail it in during the season, and still bring home the hardware. These days, if you aren't improving, you're declining, so savvy players need to be active on the waiver wire to maintain their success.

Teams heading into Week 9 with a shiny record should turn their attention to playoff matchups, while others will need to win their next few matchups to get there. This list will take a look at fantasy assets that will help in the immediate future, as well as in the long run.

Jimmy Garoppolo, QB, San Francisco 49ers

Yahoo! Ownership: 57%

With zero 300-yard passing games this season, Jimmy Garoppolo might not be the most exciting add for fantasy gamers. But he'll be the ideal streamer for the next three weeks, as he takes on the Arizona Cardinals twice and the Seattle Seahawks in that span. Entering the week, Arizona ranked 26th in Adjusted Defensive Passing Net Expected Points (NEP) per play while Seattle ranked 23rd, so we could see Garoppolo's best games of the season.

He could also have a healthier offense to work with, as Joe Staley is expected to return from his leg injury this week. Mike McGlinchey could also be back in Week 10, which would be on track with the initial one month timeline he was given for his Week 5 knee injury. That boost in protection, along with a new dynamic receiver in Emmanuel Sanders, makes Garoppolo a solid add.

Sam Darnold, QB, New York Jets

Yahoo! Ownership: 23%

Sam Darnold may have thrown seven picks over the last two weeks, but he won't be seeing ghosts again any time soon.

The New York Jets play the Miami Dolphins twice, along with the New York Giants, Washington Redskins, Oakland Raiders, Cincinnati Bengals, and Baltimore Ravens over the next seven games. All of those teams rank in the bottom-half in Adjusted Defensive Passing NEP per play.

This is a dream scenario for Darnold, but his line will need to do better than the 31st-ranked pass protection that he's been receiving, per Football Outsiders. If they can keep him upright, he has a chance to crush his second-half schedule.

Mark Walton, RB, Miami Dolphins

Yahoo! Ownership: 29%

With Kenyan Drake getting traded to the Cardinals on Monday, Mark Walton is stepping into the role as the clear lead back. His only competition comes in the form of Kalen Ballage, who is getting 1.7 yards per carry and has caught only 3 of his 10 targets entering Week 8. Meanwhile, Walton's 57.14 percent Rushing Success Rate in Week 7 ranked first among backs with at least 10 carries, and he has also hauled in 9 of his 11 targets this season. Basically, he's been better than Ballage in every phase of the game.

His ceiling is capped playing on a tanking Miami squad, but any starting NFL running back is worthy of a roster spot in fantasy football.

Tra Carson, RB, Detroit Lions

Yahoo! Ownership: 0%

While everyone was fighting over J.D. McKissic and Ty Johnson, Matt Patricia decided to give the start to an undrafted back that he signed 10 days ago. Tra Carson didn't offer much fantasy production, but he still led the backfield with 14 carries while his teammates combined for 12 total touches.

At 227 pounds, Carson has a significant size advantage on both Johnson (210) and McKissic (187), which is likely why Patricia opted to give him the heavy workload. Matthew Stafford has been slinging it lately, leading the seventh-ranked offense in terms of Adjusted Passing NEP per play. This could lead to more red zone opportunities for Carson, meaning fantasy gamers should look his way if they're in a bind with bye weeks.

Danny Amendola, WR, Detroit Lions

Yahoo! Ownership: 9%

One of the biggest beneficiaries of Stafford's strong outings has been Danny Amendola. The veteran slot savant has caught 16 of 19 targets for 200 yards over the last two weeks. He'll have a chance at extending his hot streak in Week 9, as he takes on an Oakland Raiders defense that ranks 30th in Adjusted Defensive Passing NEP per play. With Julio Jones, Michael Thomas, and the Rams receivers on byes this week, Amendola is a strong PPR replacement plan.

Josh Reynolds, WR, Los Angeles Rams

Yahoo! Ownership: 0%

Football is a violent game, and Brandin Cooks seems to sustain multiple scary hits every season. He was knocked out of Week 8 after a nasty helmet-to-helmet shot from Jessie Bates III, thrusting Josh Reynolds into a featured role.

Reynolds doesn't have the burners of Cooks, meaning every Rams receiver will likely cannibalize each other's target shares in the intermediate zones. They also have a Week 9 bye, meaning Cooks has a chance to return in Week 10 on the road against the Pittsburgh Steelers. But given Cooks' history of concussions, he could be in for a lengthy absence. Any piece of the Rams' offense is worth stashing.

Alex Erickson, WR, Cincinnati Bengals

Yahoo! Ownership: 7%

Tyler Boyd has caught 11 of his 23 targets over the last two weeks for 120 yards. Alex Erickson has caught 14 of his 21 targets for 244 yards over that same span.

Erickson now has the best catch rate and Reception NEP per Target among Cincinnati Bengals pass catchers. He has likely carved out a significant role given his recent success, and we know the Bengals will be losing often. That should lead to more Andy Dalton drop backs and Erickson targets. Plus, he'll have two solid matchups with the Ravens and Raiders over the next two weeks.

Chris Herndon, TE, New York Jets

Yahoo! Ownership: 28%

As per usual, the tight end position is a dumpster fire in 2019. If you don't have one of the top five guys, you might as well be throwing darts.

But if you're struggling at the position, Chris Herndon could be the answer. He hasn't suited up yet due to a suspension and a subsequent hamstring injury, but he was a monster in 2018. According to PlayerProfiler, the Miami product ranked top 10 at his position in fantasy points per target, yards per target, fantasy points per pass route, and touchdowns last season.

The Jets have also been shopping Robby Anderson, which would free up 6.2 targets per game. Herndon could see plenty of work in the second half of the season. Picking up both him and Darnold would be a solid stack that would raise your fantasy team's ceiling.

Jonnu Smith, TE, Tennessee Titans

Yahoo! Ownership: 19%

Everyone's favorite tight end streamer in Week 8 smashed, as Jonnu Smith hauled in 6 balls for 78 yards and a score. In Delanie Walker's absence, Smith has now played over 70 percent of snaps and set new career-highs in receiving yards in back-to-back games. He'll have a tougher matchup against a Carolina Panthers defense that ranks seventh in fantasy points allowed to tight ends, but Smith is still a strong streamer option as long as Walker is unable to take the field.

New York Jets, D/ST

Yahoo! Ownership: 12%

With the Jets' cake walk of a schedule down the stretch, their defense is an easy add. They're also built to stop the run, as they rank second in Adjusted Defensive Rushing NEP per play entering Week 8. When they're able to shut down the rushing attack of their opponents, they force them into obvious passing situations, leading to sacks, strips, fumbles, and defensive fantasy points.