Tottenham defender Walker collected the accolade last weekend, but Richards believes his Manchester City team-mate should have been given recognition by his peers after an impressive first season at Eastlands.
Aguero has netted 29 goals for City since signing from Atletico Madrid last summer, and the 23-year-old Argentine forward is third in the Premier League goal scoring charts with 22, behind Wayne Rooney and Robin van Persie.
“Sergio Aguero has been outstanding and I think he should have got PFA Young Player of the Year,” Richards told City’s website ahead of the Manchester derby on Monday night.
“Even though Kyle Walker’s had his breakthrough season and has got into the England squad, he’s actually a good mate of mine and I’m happy for him – even though we’re competing for the same position.
“I think Sergio has been outstanding. Sometimes it’s hard for a striker to come in and do well right away, but he’s got over 20 goals – you can’t ask for more than that and he will be vital for us on Monday night.”
City host United on Monday knowing a win will take them back to the top of the table – and Richards believes his side’s superior goal difference could prove decisive as the title race reaches its climax.
“I think you’ve seen the manager in the last few games going mad when we haven’t scored some easy chances, but that’s because he knows it could go down to goal difference,” he continued.
“I think that’s why he gets so agitated when we do miss them, but having said that, I think the strikers have done very well this season.”
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