Ex-Oregon Ducks tight end Colt Lyerla broke out of a jail on Thursday ... and now cops are trying to bring the 24-year-old back into custody, ASAP.

Lyerla was a key part of those insane Ducks teams from 2011 to 2013 -- winning the Pac-12 championship, the Rose Bowl and the Fiesta Bowl. He signed with Packers in 2014 but got injured before the season began.

The 24-year-old was 2 months into a 6 month sentence at a minimum security jail in Oregon stemming from a heroin arrest back in March ... but he went missing on Thursday.