The 2020-21 Premier League season has once again been a good one for young players. The likes of Emile Smith Rowe, James Justin, and Phil Foden have all starred for their clubs and look set to go from strength to strength.The Premier League season has not been so good for some youngsters, though, with some struggling to regain any of the traction they once had.Here are five young players who’ve stagnated during the 2020-21 Premier League season.#1 Rhian Brewster (Sheffield United)Rhian Brewster has not scored a Premier League goal for Sheffield United yet.Considered one of the hottest prospects in English football after scoring eight goals for England’s U-17 side in their 2017 World Cup triumph, it felt like only a matter of time before Rhian Brewster became a Premier League star.Injuries curtailed his development at Liverpool, but the 2018-19 season saw him head to Swansea City on loan, where he scored an impressive 10 goals in 20 appearances in the EFL Championship.However, rather than look to fit him into an already excellent front line, Liverpool decided to let him move on in the summer. And so Brewster made a £23.5m move to fellow Premier League side Sheffield United in October.The fee was a club record for the Blades, and many people felt it would help to kickstart their Premier League season, which had begun with three straight losses.However, Brewster simply hasn’t made the impact that most observers expected. He’s been in and out of the Blades’ starting line-up, and while he’s made 17 appearances thus far, he has yet to score his first goal for the club.It is worth noting that Sheffield United’s general struggles have probably impacted negatively on Brewster’s development. But it’s safe to say that thus far into 2020-21 at least, he’s completely stagnated and doesn’t seem likely to reach his potential any time soon.We keep fighting ⚔️ UTB pic.twitter.com/DH4hpivJrE— Rhian Brewster (@RhianBrewster9) January 31, 2021#2 Brandon Williams (Manchester United)Brandon Williams has been strangely frozen out by Manchester United in the current campaign.A number of young players have broken through at Manchester United during the last few years, including Marcus Rashford, Mason Greenwood, and Scott McTominay. And in the 2019-20 season, it looked like Brandon Williams would join that list.The left-back broke into United’s first team in late 2019 and appeared to be going from strength to strength under Ole Gunnar Solskjaer – even keeping out the older and more established Luke Shaw at points.Some fans even considered Williams an outside bet for England’s squad at the eventually-postponed Euro 2020 tournament; such was his form.However, for reasons known only to Solskjaer and United, Williams – who is now 20 years old – has been frozen out almost entirely during the current campaign.He made 25 appearances last season, including 11 Premier League starts. This season, however, has seen him appear just five times, mostly as a substitute. In fact, he hasn’t appeared since United’s FA Cup win over Watford on January 9th.With Shaw now resurgent and new signing Alex Telles providing competition for him in the left-back slot, it doesn’t look like Williams will get many chances in the near future, either.With a loan away from Old Trafford now impossible until the summer, it sadly looks like Williams will continue to stagnate for the foreseeable future.Manchester United boss Ole Gunnar Solskjaer has confirmed full-back Brandon Williams will not be allowed to leave on loan this month. (Sky Sports) pic.twitter.com/Pi38XOEqgv— Transfer News Central (@TransferNewsCen) January 31, 2021