Tebow's been trying to make it to The Show since 2016 ... when he decided to quit playing football to pursue the chance of being the MLB's next big slugger.

But, the road has been pretty rocky for the former Heisman Trophy winner ... in the 2016 and 2017 seasons in the Mets' minor league system, he stunk up the diamond.

2018 was MUCH more promising for the ex-NFL first-round pick ... he batted .273 and hit 6 home runs in 84 games -- but his year was cut short because of a broken hand.

Last season, meanwhile, was another down year for Tim ... he batted just .163 in 77 games and was forced to miss most of the season yet again because of another hand injury.

But, the Mets seem determined to give him every chance in the world to make their Opening Day roster ... 'cause the invite they handed down to him Friday is no joke.

Tebow was 1 of 8 non-roster invitees to the Mets' 2020 Spring Training camp ... and the other seven dudes that got the coveted honor are LEGIT prospects.

So, with Tebow being treated like one of the org's best ... could this be the year he gets Big League ABs???