If you have a link to it I'd like to see it. Players like Bryant have done the deal plenty as I posted here several times taken from wikipedia (i know not the best source).
I actually did find some data on this but unfortunately can't find a single link although all of these names can be researched individually if you would like.. It was also discussed at length on Bruce Levine's Inside the Clubhouse on WSCR two weeks ago and I think there is a podcast of that. In the last ten years, of
Boras clients before their first FA period four have signed extensions earlier than one year before their FA date, Carlos Gonzales, Jared Weaver, Elvis Andrus and Ryan Madsen. All admittedly asked Boras to negotiate those deals against his advice (there's an interview with Gonzales out there that's easy to find and he's clear on this). In the last few years Xander Bogaerts and Bryce Harper have turned down lengthy deals. Bryant is probably the best prospect of all of those guys with the possible exception of Harper. Will Bryant want to sign one? No one knows, not me, not anyone but Bryant and his people.
Now as far as players approaching their FA period signing with their existing teams, there have been more of those guys. Levine said there had been 6 of those in the last 10 years. He has however taken a lot of guys to new teams for huge money as Max Scherzer can tell you. His guys make more on average than those represented by toher agents although you have to figure that Giancarlo Stanton's agents at the Wasserman group did OK for their client.