The Boston Celtics have found it really hard to maintain a healthy core all year long. The group of of Kemba Walker, Jayson Tatum, Jaylen Brown, Marcus Smart and Gordon Hayward has only played 14 games together so far.Adding to their list of injuries, Jaylen Brown is now expected to miss at least one week, owing to his hamstring issue.#NEBHInjuryReport update: Jayson Tatum will play tonight. Jaylen Brown (right hamstring strain) will likely be reassessed in a week, according to Brad Stevens. Gordon Hayward (right knee contusion) is considered day-to-day.— Boston Celtics (@celtics) March 4, 2020The 2016 third overall pick had only missed three games this year for the Celtics, before going down with a hamstring issue recently. He has started in all 50 games he has played for Boston this year, and averages 20.4 points, 6.4 rebounds and 2.2 assists in 34.0 minutes per contest so far.Also read: NBA Injury Update: Gordon Hayward likely to miss game against Cleveland due to right knee contusionHis numbers have seen an apparent surge this season, and he is now an integral part of the Celtics' final dash for an improved playoff seeding. They are currently one game behind the second seed Toronto Raptors (43-18), having slipped to the third spot after losing three of their last six matchups.Coach Brad Stevens has done a brilliant job of leading an injury-ridden lineup to an imposing 42-19 record at the moment.