Henderson spent last season on loan at Sheffield United, keeping 13 clean sheets in 36 appearances as the newly-promoted side impressed in finishing ninth in the Premier League.
And while Blades boss Chris Wilder was keen to keep the 23-year-old at Bramall Lane, the shotstopper ended up returning to Old Trafford, with many expecting him to challenge the struggling De Gea for a starting place.
But the England international has made just four appearances this term – one in the Premier League, one in the Champions League and two in the League Cup.
His sole Premier League outing came last weekend as he replaced the injured De Gea at half-time, and former United defender Neville expects such opportunities to be the limit for Henderson for the time being.
“I think De Gea is the No 1 as Henderson has a lot to do in my mind – I don’t get carried away by a young and talented goalkeeper at Manchester United,” he told Viaplay Fotbal.
“I’ve seen it before over the last 25 years, where there have been young and talented goalkeepers who have threatened to come in, but to stand in those goals at the club – in particular when fans come back into the stadium – then they are big, big boots to fill.
“Only Edwin van der Sar and Peter Schmeichel have filled those boots in my time, while David de Gea has now.
“I think he’s [De Gea] probably been better this season. I was nervous about him towards the end of last season and I think even Ole would’ve been looking at him and thinking: ‘You’re not far away from being left out.’
“But I think now he’s stuck with him, which I think is the right thing to do. If you’re going to take someone like him out then you have to make sure that you’re absolutely certain, because once you take him out of the team you really are moving his confidence away and he may as well leave the club.
“For me, I think it’s exciting that Henderson is coming through, but I reserve my judgement on whether he can become somebody who can go in Manchester United’s goal in the next 10 years.”
De Gea crashed into the post in the first half of United’s comeback victory over Southampton last weekend, failing to keep out a James Ward-Prowse free-kick, and was replaced by Henderson at the break.
But the Spain international returned on Wednesday night in United’s 3-1 Champions League loss to Paris Saint-Germain.
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