Foster said: “I spoke to Alex last week as I went up to Carrington for a few scans on my knees.
“When a Manchester United player gets an injury, they like to see them. So I had their doctors assessing the situation. While I was up there we had a chat.
“He said he was happy that things were going well and said he hoped I would be fit for Chelsea to do Watford – and Manchester United – a big favour. We had a joke about that and obviously, I will try and keep him happy.
“Chelsea will be difficult – we know that. Their reserve team would probably be in the top three of the Premier League, which speaks volumes for the strength and depth they have. Drogba is on fire and can’t stop scoring.
“But we had our first win on Saturday against Middlesbrough and the boys are all buzzing.
“Chelsea had a disappointing result. I thought they had a strong start but Tottenham never gave them a second’s breath. They were constantly in their faces. If we can do the same we have got a chance.
“We have only won once but we should have won seven or eight – and we all believe we could still finish in the top 10.”