Terrell Suggs -- Sues Dead Agent ... You Left Me Out In the Cold

NFL stud Terrell Suggs is suing his former agent ... who died in 2011 ... claiming he shouldn't have to keep paying commission from his $62 million contract -- because he's been useless ever since he passed away.

According to docs filed in federal court in Virginia and obtained by TMZ Sports, Suggs sued the estate of former super agent Gary Wichard ... the guy who negotiated Terrell's mega-contract with the Baltimore Ravens in 2009.

Suggs says he was obligated to pay Wichard 3% of his salary for the entirety of his deal -- but in exchange, Wichard's agency would actively manage his career and take care of everything from seeking endorsement deals to booking doctor appointments.

But when Wichard passed in 2011, Suggs says the agency kicked T-Sizzle to an "inexperienced and unqualified agent."

Suggs says the new agent completely dropped the ball -- and when he had his best season in 2011, the agent failed to score him any major endorsement deals that usually result from "such outstanding on-field play."

There's more ... when Suggs tore his achilles in 2012, Terrell says he leaned on his agent to "take the lead on contacting doctors, setting up appointments, coordinating rehabilitation, and all other related matters" ... but got no help.

Despite the allegations, Wichard's estate has demanded $192k from Suggs, which he refused to pay. The dispute went to an arbitrator -- who ultimately ruled against Suggs.

Now, Suggs is taking the matter to court -- hoping a federal judge will throw out the arbitrator's decision and wipe his balance to zero.