The striker became United's all-time record goalscorer last season with a late free-kick against Stoke City, and sits second on the list of all-time Premier League scorers, behind only Alan Shearer.
His achievements are not limited to club football, either, the 31-year-old having overtaken Bobby Charlton as England's leading marksman in 2015.
Summer for me is about time with family . pic.twitter.com/dtft1CZoyl— Peter Crouch (@petercrouch) June 19, 2017
Rooney and Crouch often linked up together during the latter's 54-cap international career and he believes the United veteran does not get the credit he deserves.
"When you look back at Wayne Rooney's career I think maybe he's been a bit under-appreciated," Crouch said at the Costa Smeralda Invitational 2017.
"He's Man United's record goalscorer - what a club that is to be record goalscorer of - he's England's record goalscorer.
"Not just that, his natural ability. I remember when he burst on the scene when he was a 16, 17 year-old.
"He's had an incredible career and is one of the best players England has ever produced. I think there will come a time when we look back and remember just how much he has done in the game."