The defender ended his loan with Derby County this week.
"I enjoyed it at Derby," Keane told MUTV. "It was a good experience because there weren't many Reserves games so it was good to get out and get some games. We had big matches, like playing Chelsea in the FA Cup, but it was frustrating to be sat on the bench so I decided it was best to get back here to United.
"You never know [if injuries could pave the way for a first-team place]. All I can do is train in front of the manager every day and show what I can do. I need to keep playing like I have done on Monday and go in every day to impress him. Hopefully, I can get my chance.
"The loan window opens again this week but I'll give it a few weeks at least and then reassess it."
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