In a physical sport like football, injuries are inevitable, which is why most top clubs keep large squads so that they remain competitive even when their key players get injured.Considering the demands of the modern game, most first-team players, especially ones playing in the top European leagues, play up to 50 games a season. That requires players to stay in peak physical condition so that they do not burn out at the fag end of the season when titles are decided.Nevertheless, despite the meticulous planning and game management in place, key players do get injured. Quite a few such players got injured last season, missing large swathes of the campaign, but are slated to return to action this campaign.On that note, let's have a look at five such players, in no particular order:#5 Harvey BarnesHarvey Barnes is a young sensation eyed by several big clubsHarvey Barnes is one of the most exciting young players in the Premier League. The 23-year-old winger, who plays for Leicester City, has made over 100 appearances for the 2015-16 champions, registering an impressive 36 goal contributions (15 goals, 21 assists).Barnes played 25 games last season before he suffered a knee injury in Leicester's defeat to Arsenal in a Premier League game in March. However, a setback in his recovery meant he had to undergo a second surgery, which ruled him out of the season.That meant Barnes, who scored a career-best nine league goals last season, also missed Euro 2020 for England. The winger has returned to action this season but is apparently not yet up to full fitness.Harvey Barnes is NOT "up to speed physically" just yet. "You see him in training and one v ones, he’s such a threat. I thought he was excellent in the game last weekend. I’m sure this will be a big season for him.”🚑 Table: https://t.co/sxhomfssfP#LCFC— Ben Dinnery (@BenDinnery) August 12, 2021Manager Brendan Rodgers will hope Barnes, who is the subject of interest from Liverpool, is back to full fitness soon, as the player is an integral one in the Leicester City set-up.#4 Anthony MartialAnthony Martial had an indifferent season in 2020-21Anthony Martial had an injury-plagued 2020-21 campaign for Manchester United, managing only five strikes in 32 games across competitions. However, he hasn't featured for the club since sustaining a knee injury while playing a FIFA World Cup 2022 qualifier for France against Kazakhstan in March.Manager Ole Gunnar Solskjaer recently provided an encouraging update on Martial, saying:“Anthony Martial has also joined us, but he has not joined the team training yet. He’s recovering from the knee injury and that looks good.Anthony Martial's return from injury 'better than expected' #mufc https://t.co/hjMQ9ACRCZ— Man United News (@ManUtdMEN) August 8, 2021Despite an underwhelming campaign last season after a stellar one in 2019-20, Martial, who has scored 78 times in over 250 games for the club, remains a key player for Solskjaer.