The Irishman was brought in as a 17-year-old from the Waterford Bohemians back in 1999 and went on to collect 393 games for United, winning five Premier League titles.
He was not flash, but O’Shea was versatile and reliable, and Sir Alex Ferguson absolutely loved what he brought to the table.
But Carrick, a longtime teammate with O’Shea since signing for United in 2006, felt he was not getting the credit he was entitled to.
“Sheasy was a fantastic boy but did not get the respect he deserved outside of United except in Ireland where he is a legend,” Carrick wrote in his 2018 autobiography Between the lines.
“That year, Sheasy right-back played pretty much every single game and he was amazing.
“Midfield, left-back or center-back, Sheasy would play anywhere for the team. He understood what it meant to play for United, what it took to win and how to act.
“He was a model pro off the pitch and I could see why Sir Alex kept Sheasy at United for 12 years because he never had to worry about him, never had to look after him.
“The boss just knew when he needed him that Sheasy was ready.”
O’Shea moved to Sunderland in 2011 after leaving United and later switched to Reading, where he is now the first team coach.
Carrick, meanwhile, secured a 2-0 victory over Villarreal in his first match as temporary United boss Villarreal after the firing of Ole Gunnar Solskjær.
The result led United to qualify for the Champions League knockout stages. Although he will only take responsibility for one more match, O’Shea has said he believes Carrick will do the job because he is “very calm, very calculated and ultimately very focused on the team.”