1. third string - Noun
2. third string - Adjective
third string
(idiomatic) Of a decidedly lower quality or condition.
third string (plural third strings)
(sports) A unit of players that plays behind the first and second strings; a junior varsity team.
belonging to the third string of a team; one who plays behind the first and second strings.
The young college quarterback was on the third-string, and played only during blowouts.
a substitute or replacement.
Source: en.wiktionary.orgthird-string
Birmingham and Las Vegas were both on their third-string quarterbacks by the end of the ten-week season. Source: Internet
Parcells went as far as to demote Simms to the third string position, promoting Jeff Rutledge over Simms to be Brunner's backup. Source: Internet
A strong candidate for third-string quarterback of the year, Brin entered in the third quarter of Tulsa’s game against Tulane on Thursday and completed 18 of 28 passes for 266 yards and two touchdowns. Source: Internet
In its most developed form, the vihuela was a guitar-like instrument with six double strings made of gut, tuned like a modern classical guitar with the exception of the third string, which was tuned half a step lower. Source: Internet
Fast forward – this young quarterback has gone from a third-string rookie taken in the fourth-round pick to the starter on arguably the best team in the NFL, the Dallas Cowboys. Source: Internet
Same goes for third-string running back Tony Jones Jr. (hip pointer). Source: Internet