Using present perfect after simple past

I would've said had suffered myself. In English, you're allowed to mix tenses I believe.

When it was confirmed that he'd suffered a broken shoulder, I assume the confirmation read something like "mark cavendish has suffered a broken shoulder". this sentence recalls this confirmation, which was in the present tense, that happened in the past.

It's like how with reported speech the person reporting could either say what the person said at the time they said it: he said she needs a pencil, or change it slightly as an acknowledgement that what happened is no longer relevant to the present: he said she needed a pencil.

"Has + PP" is used for HOT TOPICS, relevant current events, past actions that have current relevance.

Mary's had a baby! [even if it is a month old]
God damn it, I've cut my finger.

"was confirmed" is the passive.

It could be,

Since it has been confirmed that X broke a shoulder he has been scratched from further competition.

That is true, but only if it makes sense.