Over the past three years, the Seahawks have drafted eight players in the third round — a league-best haul created by comp picks and draft trades that figured to help forge the next core of Pete Carroll’s team.

But it hasn’t so far — at least not as much as Carroll and John Schneider surely hoped it would.

With about 20 percent of this season complete, only one of those eight guys has become a starter and only two others are even contributing much.

That has to be disappointing after Schneider set up Seattle for some quality drafts in 2016 and 2017 — 11 picks in the first two days. Of seven third-rounders from those drafts, Shaquill Griffin is the only one to crack the first string (he has two interceptions this season).

Since Schneider and Carroll arrived in 2010, the Hawks have uncovered three starters from 12 third-round picks. Russell Wilson (2012) has been the best third-rounder in the NFL over that time, and Griffin (2017) and Tyler Lockett (2015) have become great starters for Seattle as well.

That 25 percent starter rate is close to the league average of 28 percent (via a study that covered the 2005-14 seasons). But the 1 for 8 from the past three third rounds is an underachievement, especially considering the league-wide success rate has improved this decade.

As for the others …

Rees Odhiambo already is gone. Amara Darboh almost was, but he somehow reverted to Seattle’s IR after a strange trip to New England. C.J. Prosise continues to be sidelined by minor injuries and somehow still has a roster spot. Nazair Jones apparently has regressed (he played six snaps vs. Dallas), and Delano Hill has been inactive the past two weeks.

Nick Vannett and rookie Rasheem Green (51 percent of the snaps so far) are the only guys other than Griffin who are contributing to any significant degree — and Vannett has been bumped from the No. 1 tight end spot by rookie fourth-rounder Will Dissly.

Since 2010, the NFL’s average third-round contributor rate has jumped to around 50 percent, based on a study using Pro Football Reference’s approximate value stat. So, by that measure, Seattle’s 42 percent (5 for 12) is a bit below average — and the 37.5 percent rate over the past three drafts obviously is not good enough.

The Hawks clearly could have made better picks at times. Instead of Prosise and Odhiambo in 2016, Seattle could have had QBs Jacoby Brissett or Dak Prescott, C Graham Glasgow, LBs Joe Schobert or De’Vondre Campbell or RB Devontae Booker.

Of course, the Hawks have found other guys to play in place of those so-far disappointing third-rounders.

Prosise, who has missed 22 of 35 games, was replaced last week by 2017 pickup Mike Davis, who should remain the No. 3 back anyway. Even with Tom Johnson cut, Jones has not been able to challenge veteran Shamar Stephen for the top spot next to standout Jarran Reed. Hill has been superseded as the third safety by 2017 fourth-round pick Tedric Thompson. Darboh couldn’t stay healthy and was knocked off the roster by 2017 sixth-rounder David Moore. And Odhiambo, a reach in the 2016 third round, was dumped in favor of new pickup Jordan Simmons (who has been inactive so far).

So how do these third-round stumbles affect Carroll’s new core?

There is still hope for Jones to get back into the coach’s good graces and play like he did as a rookie. If he doesn’t, though, the Hawks will need to find a starting tackle next year (or sign Stephen again).

With Earl Thomas headed out sooner or later, Thompson will be expected to take his spot and Hill will remain a reserve behind Bradley McDougald, assuming he is the best option.

Green figures to start by next season, either opposite or in place of Frank Clark (a pending free agent).

If those third-rounders come through, it would save Schneider from having to draft to replace them (which he kind of started this year), and it would make the third-round success rate from the past three drafts much closer to what Schneider and Carroll expected when they made those picks.