Rob Ninkovich no longer plays for the Patriots, but he wishes Jimmy Garoppolo still did. Today, the retired New England linebacker who was Garoppolo’s teammate from 2014-16 said his ex-team erred by trading Garoppolo to the 49ers for a second-round pick Oct. 30. “I think that was a mistake trading Jimmy because Jimmy’s an unbelievable quarterback,” Ninkovich said on Boston-based sports radio station WEEI. “He’s a guy that you can build a franchise around. Obviously, he’s going to be the franchise guy in San Francisco.” Ninkovich, who played with the Patriots from 2009-16, acknowledged he didn’t have a solution to the conundrum the Patriots faced before dealing Garoppolo. Tom Brady, 40, is an MVP candidate this season and Garoppolo is in the final year of his contract. New England’s could have placed the franchise tag on Garoppolo in the offseason, but that would have meant they would have given at least $23 million guaranteed to a quarterback destined to be a backup for a fifth straight season in 2018.