49ers All-Pro likely to stage hold-in if unsigned by training camp

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 extension has been on the 49ers’ docket for multiple offseasons. The team has long viewed this year as the likely extension window, seeing as the All-Pro defensive end had the fifth-year option in his rookie contract. But Bosa remains unsigned.

It is not too unusual for a first-rounder to enter his fifth training camp still tied to his rookie contract, but other defensive linemen from Bosa’s draft class locked in…