You're giving waaaay too much credit to doctors. This isn't a clear yes/no situation. The patella tendon is a critical part of knee stabilization and anchoring to your quad to your tibia. If it was so easy to diagnose injuries (in general), doctors wouldn't be getting it wrong over and over and over. You're talking the best doctors in the world working in a multi-billion dollar industry and they still get it wrong.
In this case, a doctor likely won’t say a lot more than “it’s healed”. But, the complexities of the injuries still come down to rebuilding strength rapidly around the injury... working through a possibly now stiffer tendon... working out any new imbalances... mental confidence... etc. You even have recent examples like Bradley Chubb who missed an entire year+, but then why expect Simmons to be very valuable before we see him hit a calendar year? ... "way ahead of schedule" or not. And if he's not at a point where he can perform at 100%, there's no way to adequately assess the risk in a workout. I'm not sure what doctor can go in there and tell you beyond a shadow of a doubt that everything will be ok.
Also, this isn't just day 3 picks that are bums either. Look up other recent OL with the injury: Cole Strange (1st round pick) and Lucas Niang (3rd round pick). I'm not saying Simmons won't ever play, but it is to say he'll likely never reach what his potential was. He probably won't be a premiere LT in the league worthy of the drooling and high expectations. Of course, the Bears can gamble that he will, but they've already gambled once on a huge tendon tear with Kiran. I'm not sure it's wise to double down at the same position.
Here's what doctors say:
Also:
"A study just published in June of this year [2016] in the American Journal of Sports Medicine looked at orthopedic procedures on over 550 NFL athletes.
And of all the different surgeries that these guys have, those who fared the worst when it comes to rate of return to play and performance metrics like yards gained and touchdowns scored, [it was] patellar tendon repair.
And their careers were shortened overall significantly. It's not to say that one individual can't come back and be phenomenal, but it's telling you that the odds are against them in terms of returning to form."
Also:
According to Dr. Spindler, the study findings are a reality check for physicians and patients. The data may change expectations for recovery and reinforce the need for long-term rehabilitation after surgery.
“The fact is, these are massive injuries,” he says. “
In spite of repairing and healing, the tendons often don’t come back anywhere near normal, and patients still have significant disability.”
New data on patellar and quad tendon ruptures may change expectations for recovery. A study finds that both injuries require significant rehabilitation time, and many patients never fully recover.
consultqd.clevelandclinic.org
Here's a 2nd round pick:
Injury update not good for 49ers former 2nd-round pick
Here was the highest paid center in the league:
49ers center Weston Richburg announced his retirement Wednesday, saying that he had "reached a point where my body won't allow me to continue playing and competing at a high level."
www.espn.com
Here's another 2nd round pick, multi-time Pro Bowler, LeCharles Bentley, who was forced to retire cause of this injury.