As the NFL preseason starts kicking off its first full week of games, NFL rookies will be the focal point, as many will play big roles. We will get a better sense of where the rookies are in their adjustments to the NFL, but there are a few who are getting major buzz and positive criticism. Not every NFL rookie is guaranteed a roster spot, but these players could end up as future starters.Ten rookies to watch in 2021 NFL preseason#1 - WR Elijah Moore - New York JetsZach Wilson ➡️ Elijah MooreEvery. Single. Day. pic.twitter.com/KCTC0wxNCg— The Jet Press (@TheJetPress) August 4, 2021New York signed Keelan Cole and Corey Davis in the offseason but 2nd-round rookie Elijah Moore has already knocked off Denzel Mims as his competition. Moore could take over the slot duties with his speed and size combination and could even knock off Corey Davis or Keelan Cole for an outside role. Moore caught 73% of contested catches in his final year of college and is already having a great NFL preseason.#2 - WR Terrace Marshall - Carolina PantherTerrace Marshall RZ fade w/ Jaycee Horn in coverage. 🎥: @panthers pic.twitter.com/CkW6E0buOi— John Ellis (@1PantherPlace) August 8, 2021It seems Terrace Marshall hasn't been talked about much since he was drafted. The six-foot-three WR has had most of playing experience in the slot and can be a great weapon in the red zone, as he did for LSU. Robby Anderson and DJ Moore are the starters but Marshall could be a mismatched star in the slot. In the NFL preseason, watch Marshall when he takes off downfield.#3 - QB Trey Lance - San Francisco 49ersTrey Lance showing out today 👀🚀pic.twitter.com/n2o4lUEg8o— PFF (@PFF) August 3, 2021NDSU QB Trey Lance still seems to be the backup to Jimmy G. The team doesn't think Lance is the best option for the starter, even though he has outshined Jimmy G in training camp, especially with his deep ball. Lance should play well in his NFL preseason role and, even if Jimmy G still gets the nod, eventually beat him out for the job by November.#4 - RB Javonte Williams - Denver BroncosHow do Courtland Sutton, Jerry Jeudy and rookie RB Javonte Williams look early in camp? Williams was considered by the Broncos as the best back in the draft. They really like him. The other two are stars. My report on @nflnetwork at #broncos camp pic.twitter.com/QPBlLAycoG— James Palmer (@JamesPalmerTV) August 4, 2021Even though Melvin Gordon was a quality starter in 2020, Denver drafted Williams in the second-round. He's received praise for his instincts and reflexes on the field, on top of his running ability. His pass-protection is an added bonus. He will end up sharing the backfield with Gordon in the NFL preseason, but Williams is too talented not to be on the field more often.#5 - WR Dyami Brown - Washington Football TeamDyami Brown with an absolutely filthy diamond release for the win here. Just NASTY stuff from the rookie. pic.twitter.com/pF56jyswrx— Ray G 🏁 (@RayGQue) August 7, 2021The third-round WR has been able to remain open against the secondary all throughout camp for big yardage. Dyami Brown is even making plays across the middle. He won't be a starter in 2021 but could have a great year as someone who can catch almost anything thrown his way. Curtis Samuel's injury will allow Brown to have more of a prime role in the NFL preseason.#6 - LB Micah Parsons - Dallas CowboysMicah Parsons first fumble recovery of NFL career! pic.twitter.com/pvdjYYkgh8— Barstool Penn State (@PSUBarstool) August 6, 2021Micah Parsons has been a constant highlight reel during training camp as an LB/EDGE. He seems suited for an every-down role on the defense. In his first NFL preseason game, Parsons had three tackles and a fumble recovery. Head coach Mike McCarthy wants him on the field Week 1 and will likely be a starting edge rusher.#7 - EDGE Joe Tryon - Tampa Bay BuccaneersAdd JPP to the list of Bucs people singing the praises of Joe Tryon: “He’s gonna be amazing” pic.twitter.com/mvFN79XVBh— PewterReport (@PewterReport) August 6, 2021Joe Tryon hasn't had his name brought up much as the final pick in the first round to the defending Super Bowl champions. The roster is loaded from top to bottom and there is already Jason Pierre-Paul and Shaquill Barrett coming off the edge. Tryon hasn't played in pads in almost two years, but head coach Bruce Arians says he was playing better than most in camp. He's been playing all-out since minicamp and will see a large role as the backup for Pierre-Paul, 33 going into the NFL preseason.#8 - WR Nico Collins - Houston TexansAnother day another Nico Collins touchdown 👀 https://t.co/Iu6pRUiWZr— EverythingTexans (@EvTexans) August 2, 2021Nico Collins is a third-round, six-foot-four WR who has gotten better with his routes and coverage in each practice. He is in line for first-team reps come the first NFL preseason game. It's honestly hard to scout any player on this offense with so many question marks, although Collins is a glimmer of positivity.#9 - TE Kyle Pitts - Atlanta FalconsOMG. KYLE. PITTS. pic.twitter.com/npujj07TdJ— Atlanta Falcons (@AtlantaFalcons) August 3, 2021Of course the fourth-overall pick will be a rookie to watch as one of the most explosive receivers in the draft class. He's been a headache for DBs and is catching anything thrown to him. He might not see much playing time in his first NFL preseason game, but could play a lot in Week 2. The Atlanta Falcons should have one of the highest-rated NFL preseason games as people get their first look at Pitts.#10 - OL Trey Smith - Kansas City ChiefsTrey Smith vs Chris Jones pic.twitter.com/DzioTJF2SA— Eddie High (@EddieHigh) August 3, 2021Trey Smith was drafted in the sixth round, even though he was projected in the second/third round. He fell due to health concerns with blood clots in his lungs. He's performed outstandingly in first-team reps at RG and won most one-on-one battles. In a revamped OL, Smith is currently in the lead to win the RG job over Yasir Durant and veteran Laurent Duvernay-Tardif heading into the NFL preseason.