Phil Jones feels 'fit and strong' and ready to step back into the fold when needed by Manchester United in a crucial stage of the season.
It was not until last week's Premier League encounter with Queens Park Ranger that Sir Alex Ferguson had more than four defenders to choose from.
Michael Carrick and Antonio Valencia have been forced to fill in at times, so stretched have the Red Devils' resources been.
Yet, with Chris Smalling now back from a broken metatarsal and skipper Nemanja Vidic in line to face Cluj in the UEFA Champions League on Wednesday, Jones is not guaranteed any involvement despite being available again after summer knee surgery.
"That's football," he said. "It's swings and roundabouts with injuries. It's amazing how quickly you can be up there one minute and then down there. Everyone knows that.
"I've just got to knuckle down, train well and, when I get the chance, perform well."
Jones is ready for the challenge, though, as he added ahead of Saturday when he will hope to be involved in top-of-the-table United's Premier League game at Reading: "I feel fit and strong.
"Obviously I haven't played a lot of minutes yet. But I felt good in the game I have had, and it was quite a difficult one to come back into.
"It is going to take a while to get my match fitness back but hopefully I can pick up some more minutes as the season progresses."
What will be the outcome in the match Reading vs Man Utd?