Shackleton, 22, is in much need of first-team minutes due to how little he has played over the last few seasons at Leeds. His development has stagnated given the limited number of minutes he has played, but also because injury has hampered him for much of his Leeds United career to date.
Although naturally a central-midfielder known for his stamina and high energy when playing box-to-box, Shackleton was used in a number of different ways under Marcelo Bielsa. He regularly showed versatility and willingness in other roles: mainly as a right-back, or right-wing-back, and also occasionally as a more traditional wide midfielder.
At Millwall he is hoping to get his career back on track and play in his more favoured position, where his pace and energy aid him in being a pressing machine.
How exactly has life started for the young Englishman? We take a look…
How’s it going?
Shackleton has yet to score or assist for Millwall, but that was never his game for Leeds, either. During his time with the Whites he obtained two goals and two assists in 79 games.
The main positive is that he has played in all 10 league games, in which he has played central-midfield/defensive-midfield in six of them, playing in a wing-back or wide midfield role in the other four. He is getting much more action in the area he wanted to be in than he was being provided at Leeds.
Despite being in an all action and high intensity area of the pitch he has only picked up one yellow card so far, too. He has shown discipline and maturity in his displays so far.
Is he a guaranteed starter?
Almost ever-present. Shackleton has started every league game but one for Millwall so far. He came off the bench in a 2-0 defeat to Norwich City in his only substitute appearance.
He has completed five full 90s and played over 75 minutes in a further three games. The number of minutes he is accruing are far beyond anything Leeds were able to offer him.
He is clearly a trusted member of Gary Rowett’s squad and firmly in his plans, which is more than can be said of fellow Leeds loanee Charlie Cresswell.
How will Leeds view this deal?
There is uncertainty around Shackleton’s future at the club given he will only have a year remaining on his current deal at the end of this season.
The loan is more beneficial to Shackleton than it is to Leeds, as his value is unlikely to fluctuate too much when a prospective buying club have the upper hand in negotiations due to Shackleton’s contract length, so even good form is unlikely to aid Leeds to a large extent in this area.
With regards to his contract length, it would have made more sense to have sold the 22-year-old, or loaned him out after extending his contract. The move was somewhat surprising in that sense.
I think many fans would agree that it is fairly unlikely he will play for the club again.