Darren Waller is no longer a Raider ... and there's one guy who's crushed over the superstar tight end getting traded to the Giants -- with his now-former teammate Josh Jacobs tweeting his frustration over the move.
"S***s sad fr," the All-Pro running back said just minutes after the trade news broke ... which makes it pretty clear he did not approve of the transaction.
Waller was shipped to the Big Apple for the 100th overall pick in the upcoming NFL Draft ... which means the G-Men essentially turned Kadarius Toney -- who was traded to the Chiefs last season -- into a top tight end talent and a 6th-round pick.
Jacobs isn't the only one pissed -- Raiders offensive lineman Jermaine Eluemunor also went to social media to give his reaction, saying, "Bro Wtf."
Waller, meanwhile, appears to be on his honeymoon with his new wife, Kelsey Plum ... so it might be a bit before we get his reaction to the move.
It has to be a bummer for the newlyweds -- Plum plays for the Las Vegas Aces, which means the two will be rackin' up the bonus miles to see each other.