Sherman not only had surgery from tearing his right Achilles, he just as repair to his left Achilles. All the reading I've done says that quick twitch football players simply don't come back from Achilles injuries.
In fact, power players don't either because they'll never have much more than 50% of the explosiveness in their ankle area that they had pre-injury.
This is why I really doubt that Kayvon Webster will ever play another down with the Rams.
If someone knows of a couple of Achilles injured players who came all the way back, could you tell me who?