In previous years, Sheffield has done worse on ballots that were not made public prior to the results being announced so it's likely he ends up under 75% again this year although closer than he has been before.
Sheffield's link to PEDs and BALCO is through working out with Bonds, and he has maintained he did not know he was being given a steroid to use and stopped using it when he found out. The link below is to an article by Jay Jaffe and has more information about it:
https://blogs.fangraphs.com/jaws-and...ary-sheffield/
If Sheffield were to get in, I'm not sure if that would open the door for others who either failed tests or are suspected of having used much longer than Sheffield, but after this year, it would be up to the various veteran's committees (or whatever they are called these days) instead of the BBWAA.