The Ecuador international has captained Manchester United for most of the 2017-18 season in the absence of veteran midfielder Michael Carrick.
Valencia has been used as a right-back since Jose Mourinho’s appointment as Louis van Gaal’s successor back in May 2016.
The 32-year-old scored three goals and made one assist in 27 appearances in the Premier League in the current campaign.
Former Manchester United defender Parker believes Valencia would struggle to command a place in the starting line-up of their title rivals.
“Valencia has done okay,” said Parker, speaking exclusively to 888sport.
“He is strong and he is steady. He’s improved his defending but offensive play isn’t really his strength and the same can be same for all of the full-backs at Manchester United.
“Valencia has been steady, that’s all I will say, and how the world is now with full-backs I don’t think there are many teams who would play him as a right-back.”
Valencia moved to Manchester United in an £16m deal from Wigan Athletic in the 2009 summer transfer window.
The Ecuadorian winger has scored 25 times in 324 games in all competitions over the past nine seasons at Old Trafford.
Valencia has won two Premier League titles, two Europa League crowns, two League Cups and the FA Cup at Manchester United.
The Champions League title has eluded the South American following a loss to FC Barcelona at Wembley in 2011.
Manchester United are in second place in the Premier League table and two points ahead of Liverpool FC in the race to finish as runners up.
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