Manchester United boss Louis van Gaal has given Jonny Evans, Chris Smalling and Phil Jones until the end of the season to prove their worth to the club.
According to the Manchester Evening News, Van Gaal will axe all three United defenders in six months time if they fail to improve on their recent performances.
The Old Trafford boss wants to settle on a first choice back-four, and as Smalling, Jones and Evans have struggled with injury during Van Gaal's tenure the Dutchman is unsure over their ability to play a key part under him.
He is willing to give them time to get fit and impress in the first-team, but at the same time he's already lining up his defensive targets for another assault on the transfer market next summer.
Borussia Dortmund defender Mats Hummels is the main target for Manchester United, while Diego Godin is also an option. Much depends on whether United can secure a top four spot and a place in next year's Champions League.
They currently sit third in the Premier League table, and Van Gaal has done an excellent job juggling his players in defence. Academy graduates Tyler Blackett and Paddy McNair have stepped up in the absence of Jones, Smalling and Evans.
Even Marcos Rojo have spent time on the treatment table this season, although the Argentine international is now back in the lineup.
Smalling limped off against Southampton earlier this week, and Van Gaal replaced McNair after just 38 minutes as well as the youngster was struggling against the Saints in the heart of the United defence.
Jones has been out of action since October with shin splits while Evans has recently returned to the first-team and came on as a substitute at St Mary's Stadium on Monday evening as United got a 2-1 win.
Robin van Persie scored both goals in the victory.