Bears legend Mike Singletary is ALL ABOUT Mitch Trubisky ... but warns Chicago fans that things ain't gonna change overnight.
We spoke with Singletary after Mitch-a-palooza on Monday Night Football ... and the Hall of Famer told us he was genuinely impressed with the #2 overall pick.
But the bottom line for Mike ... the Bears need to let Mitch "be what he is, a rookie," which essentially means it's a growing and learning season -- not a Super Bowl contender season.
"I definitely think there’s a lot to work with."
Pretty high praise from one of the greatest Bears ever.