Who is Tyrell Williams? If you’re asking that question, you might be too late.

The San Diego Chargers receiver has gone from 1 percent owned to 41.9 percent owned in ESPN fantasy leagues in the wake of Keenan Allen’s season-ending knee injury. No other player has seen a bigger uptick.

ESPN Chargers reporter Eric Williams endorses that investment, and he thinks the relative unknown will step into a leading role.

Chargers wide receiver Tyrell Williams made two receptions for 71 yards in Week 1. William Purnell/Icon Sportswire

“I think both Travis Benjamin and Williams’ value increases,” Williams said. “But I like Williams’ [fantasy prospects] better because he’s more physical and will win more often against press and man coverage.

“At 6-foot-4 and 205 pounds, Williams is the prototypical big target that Philip Rivers likes to throw to, with the speed to beat defenses deep.”

Williams has just four career catches after going undrafted out of Western Oregon last year, but he has made the most of them. He had two catches for 71 yards last week and two for 90 yards last season, including one 80-yard touchdown.

Here are some more players who should be on your radar after Week 1, according to ESPN’s NFL Nation crew:

WR Eli Rogers. Speaking of undrafted receivers, Rogers' NFL debut was no fluke (six catches, 59 yards and a touchdown). Pittsburgh Steelers reporter Jeremy Fowler predicted this summer that the second-year pro would play a significant role in the offense after he spent the past season on injured reserve, as Pittsburgh has been so hungry for a true slot receiver to pair with Antonio Brown. Fowler said he isn't sure how many TDs the 5-foot-10, 187-pounder will score, but he would set the over/under for catches around 60.

WR Stefon Diggs. Minnesota Vikings reporter Ben Goessling is also buying into Diggs’ impressive Week 1 performance (seven catches, 103 yards). Although Goessling points out that Diggs petered out after he got off to a hot start as a rookie last season, he said fantasy owners shouldn’t be scared off. Last season, the Vikings used the 6-foot, 194-pounder almost exclusively at split end, where he faced a lot of press coverage from top cornerbacks. Now that he has had a full season in the offense, he is being moved around a lot more. Goessling said Diggs might be the Vikings’ best route runner, which will help him earn the trust of the team's new QBs.

RB Rashad Jennings. You should consider starting pretty much every member of the New York Giants offense against the New Orleans Saints' defense this week, and that includes pass-catching running back Shane Vereen. But Giants reporter Jordan Raanan is especially high on Jennings as a long-term investment. Raanan wrote earlier this week that Jennings should be a solid weekly play, now that New York’s backfield has been whittled down to a two-man timeshare, compared to three- and four-man rotations last season. Raanan also pointed out that Jennings had 18 carries and two targets in Week 1, compared to 13 and one in Week 1 last season.

RB Theo Riddick. Detroit Lions reporter Michael Rothstein is equally high on Riddick, another running back in the same tier. Rothstein wrote that Riddick did some myth-busting last week and showed that he is more than just a pass-catcher by carrying the ball seven times for 45 yards and a touchdown, in addition to catching five passes for 63 yards and a score. “I’m killing that stereotype, that stigma right now,” Lions teammate Ameer Abdullah said. “Theo has always been a good runner.”

RB Tevin Coleman. Unfortunately for Devonta Freeman owners, Coleman might be a worthy investment as well. Coleman had 32 snaps and 13 touches in Week 1, compared to Freeman’s 36 and 15, and Coleman was more productive because of his 95 receiving yards. Atlanta Falcons reporter Vaughn McClure pointed out in this week’s NFL Nation fantasy Q&A that Freeman still has the edge when it comes to catching the ball out of the backfield, but he said Coleman has made tremendous strides in that area. McClure predicted that there could be a close split in touches the next few weeks, as offensive coordinator Kyle Shanahan would like to get Coleman’s speed burst involved.

One Week 1 breakout performer whom you shouldn’t get overly excited about is Oakland Raiders undrafted rookie running back Jalen Richard. Sure, he looked great on his 75-yard touchdown run against the Saints, but he had only five touches in the game, compared to 15 by starter Latavius Murray and six by fellow rookie backup DeAndre Washington. Raiders reporter Paul Gutierrez said Oakland still wants to feature Murray. If anything, the Raiders might give Washington a chance to get going like Richard did in the opener, especially because Washington is the one they drafted.