United really should be careful with him and prioritize his long term development. Lille played him into the ground last year. Putting 3700 minutes onto a 17/18 year old player is really irresponsible and its not all that surprising that he ended up with a significant injury. Especially given that the adaptation to the PL will be significant, United should be looking to make him part of a CB rotation but to give him plenty of rest and avoid playing him twice a week. Guys like Varane and Saliba did not play >3000 first team minutes until their fourth or five professional season, they were built up slowly physically over time.
This isn't true for quite a few players who made their debuts in their teens. The following are a few examples of centerbacks over the years:
Sergio Ramos made his La Liga debut at 17 for Sevilla and was a regular for them by 18. This continued with Real when they signed him at 19
Maldini debuted at 16 and became a Milan regular by 17 and never looked back
Our De Ligt while maybe not being the best example based on injuries in recent years, debuted for Ajax at 17 and was a starter in their 2016/17 EL campaign under Peter Bosz. He was made captain at 18 and became a regular starter in 2017/18, getting 2,913 mins in the Eredevisie alone. The following season he played 2,970 mins in the league and 990 in their CL campaign. His injury problems began in earnest while at Juventus and the majority of his 30 documented injuries were to his right knee and to his thighs.
Current Ajax CB Jorrel Hato (18) debuted at 16 and played 2962 mins in the league last season and 540 in Europe. Also consider the likes of Seedorf and Kluivert who were regulars by 16 and 18 respectively for Ajax in the 90s, playing huge roles in league titles and long CL campaigns where they made 2 back to back finals
John Terry became a PL regular at 19.
Rooney
Rio made his PL debut at 17 and at 18 made 27 senior appearances for West Ham and Bournemouth (10) on loan. He was a fully fledged starter by 19 and captain by 22 for Leeds
Perhaps Lille knew what they were doing with Yoro, maybe not, but its not unprecedented for a prodigious young player to get regular starts and not suffer through injuries from being over played.