Does infect damage dealt to a player cause poison counters even if the damage is redirected?

Infect is a static ability that changes the way damage is dealt. Under CR 702.90b, damage dealt to a player by a source with infect causes that player to get that many poison counters instead of losing that much life. This replacement effect applies based on the source of the damage, not on who the original target was.

When damage is redirected — for example, by a spell or ability that causes damage that would be dealt to one player to be dealt to another player instead — the source of the damage does not change. The redirected damage still originates from the same infect source, so the poison counter replacement effect still applies (CR 614.1, 702.90b).

Similarly, if damage is prevented and then dealt elsewhere (such as with Deflection or Boros Fury-Shield), what matters for infect is the original source's characteristics at the time damage is dealt, not the original intended recipient.

Example: Your opponent attacks with a 3/3 creature with infect. You cast a spell that redirects all combat damage that would be dealt to you this turn to another player (e.g., the effect of a redirection spell). That other player still receives 3 poison counters, not 3 damage/life loss, because the source — the infect creature — still has infect when the damage is dealt.

Note that infect damage dealt to creatures is dealt as -1/-1 counters (CR 702.90b), but this question concerns players specifically, where poison counters always apply regardless of redirection.