A quarterback's ability to deliver catchable balls to his receivers is a major factor in their overall success. This past week offers some stark examples in which a quarterback change injected some new life into one team's air corps (Drake Maye) ... and a couple others in which questionable quarterback play (Will Levis, Deshaun Watson) has been a major impediment to those offenses even getting off the ground this season.

As fantasy managers look to improve their teams via the trade market, those team dynamics are something to keep in mind.

Here are some players whose values are trending upward (or downward) as a result of their performances in Week 6.

Fantasy football players to buy for Week 7

WR DeMario Douglas, New England Patriots: Douglas instantly jelled with rookie QB Drake Maye, hauling in six receptions for 92 yards and a touchdown − after entering the day with 19 receptions, 153 yards and no scores in five games with Jacoby Brissett. Now that Douglas has an NFL-caliber QB under center, his fantasy value is taking off.

RB Isaac Guerendo, San Francisco 49ers: Jordan Mason had been filling in admirably for Christian McCaffrey, but he suffered a sprained shoulder in Week 6. Guerendo stepped in, and he stepped up with 99 yards on 10 carries. The Niners usually get the most out of their backs, giving Guerendo some short-term appeal.

RB Tyler Goodson, Indianapolis Colts: With Jonathan Taylor sidelined, the Colts called on Trey Sermon to start for a second straight game. He averaged less than two yards per carry, so Goodson saw his most extensive action of the season (65 total yards, 12 touches). He is worth scooping up to face the Miami Dolphins in Week 7.

WR Tank Dell, Houston Texans: Dell struggled during the first three games while he wasn’t quite 100%. He is healthy now, and with Nico Collins out of the picture for a while, Dell is second on the depth chart behind Stefon Diggs. He scored his first touchdown of the season in Week 6, and there should be more coming.

WR Devaughn Vele, Denver Broncos: Vele had eight receptions in Week 1, but he suffered a rib injury, and he hadn’t been seen since. When Josh Reynolds was placed on injured reserve, Vele got a second chance and made the most of it. The 26-year-old rookie is a solid option in deep PPR leagues.

Fantasy football players to sell for Week 7

WR Calvin Ridley, Tennessee Titans: Ridley was targeted eight times in Week 6 against the Indianapolis Colts, but he was blanked. Poor quarterback play in Nashville has contributed to Ridley’s downfall, but he has managed just two catches and 14 yards in the past three games. He's not worth a fantasy roster spot at this point.

QB Deshaun Watson, Cleveland Browns: We’ve waited and waited and waited, but Watson just isn’t turning the corner. He has played all six games, his offensive line is starting to get healthy, but it’s the same dink-and-dunk offense. It’s part coaching and scheme, too, but Watson is one of the worst fantasy quarterbacks, and he isn’t making a move up the charts anytime soon.

RB Alexander Mattison, Las Vegas Raiders: After Zamir White flamed out, then suffered an injury, Mattison got his shot at being the bell cow. He has struggled mightily in the past two games, posting just 2.4 yards per attempt in 29 carries. It doesn’t help he faced the Denver Broncos and Pittsburgh Steelers defenses, but he's shown no signs of breaking out.

RB Travis Etienne, Jacksonville Jaguars: Etienne banged up his shoulder, so injury could be playing a part, but he is just not effective right now. Tank Bigsby looks to have unofficially blown past the former first-round pick on the depth chart. Don’t drop Etienne, but he is fizzling, and fizzling hard.

TE Isaiah Likely, Baltimore Ravens: Likely had a huge game in Week 1, but since then, he has only nine receptions and 96 yards with two scores. Mark Andrews looked like his former self in Week 6, and Likely will likely be fighting Charlie Kolar for crumbs again.

TheHuddle.com is part of the USA TODAY Network.

This article originally appeared on USA TODAY: Fantasy football Week 7: 10 players to buy low, sell high