Every offseason we see hundreds of NFL players change teams. Those myriad roster changes can be so chaotic that even the most ardent football fans can have trouble keeping up. 

Many of these roster changes can have huge fantasy football ramifications. Having knowledge of how these signings and trades impact each team is an essential tool in the well-prepared fantasy manager's arsenal. 

Here are the top five offseason movers from the 2021 offseason and how it affects the fantasy football outlook for key contributors.

Rams trade Jared Goff for Matthew Stafford

It wasn't an even swap, as Sean McVay once again showed he has no interest in making first-round selections, but the blockbuster Detroit-L.A. QB trade has major fantasy ramifications. 

Goff has more or less been a decent but unspectacular performer for the Rams but failed to progress into a real difference-maker. Goff became the youngest signal-caller to win an NFC Championship in 2018, but his play stagnated. 

McVay knew that in order to take advantage of his team's championship window, he needed to get better quarterback play. Thus, McVay sent Goff to Detroit and acquired Matthew Stafford, who provides an instant boost as both a passer and game manager. 

In his last 18 games, Stafford has averaged 274 passing yards per contest while throwing an impressive 45 touchdowns versus only 15 interceptions. Goff, meanwhile, has posted a meager 42-to-29 TD-to-INT ratio in his past 31 contests. 

Stafford, 33, still has plenty of his prime years left and should be a terrific fit in McVay's aggressive scheme. The season-ending injury for rising RB Cam Akers will only put more emphasis on Stafford's right arm. 

With fewer turnovers and an expanded playbook, Robert Woods, Cooper Kupp, Van Jefferson, DeSean Jackson and TE Tyler Higbee should benefit from Stafford's presence. Kupp and Jackson, especially, look like excellent bargains at their current ADPs. 

The Lions appear to be in the beginning stages of a massive rebuild. Although Detroit boasts a promising young offensive line, Goff appears to be a temporary placeholder. While he is still just 26, Goff is no longer viewed as a promising prospect.

Additionally, Goff will be throwing to a haggard receiving corps topped by veteran castoffs Breshad Perriman and Tyrell Williams.

While Detroit is currently among the favorites to land the No. 1 pick of the 2022 NFL Draft, which would likely be a rookie signal-caller, the Lions will have plenty of positive game scripts which could favor Perriman, Williams, and TE T.J. Hockenson commanding plenty of targets and returning positive value on their currently depressed values.

View Stafford as an excellent late-round QB2 with QB1 upside, while Goff should only be considered as a middling fantasy option in Superflex leagues.

SportsLine Fantasy expert Jody Smith, who has finished atop Fantasy Pros' seasonal accuracy rankings and contributed to many fantasy publications in his career, pegged Antonio Gibson as an upside play when breaking down 2020's top RB committees and labeled Jonathan Taylor a star in the making. A year later, Taylor is being selected in the first round of most Fantasy drafts following a huge rookie year while Gibson is coming off an 11-touchdown season and a popular early-round target.

Which offseason move makes several players on one team "a fine bargain at their current ADP?" And which RB looks like an "absolute steal?" ... Join SportsLine right now to see Jody Smith's top five offseason moves for Fantasy, plus get the entire 2021 Fantasy Football Draft Bible, all from the longtime expert named one of the nation's most accurate Fantasy analysts!