Under three days remain until the January transfer window slams shut for another year.

At the time of writing, Nelson Abbey is the only player who has departed the club, although Tom Holmes will head to Luton Town in the summer after agreeing on a deal this month.

It is expected that fellow Academy graduate Tom McIntyre will also head out of the door before Thursday, set to join league leaders Portsmouth.

READ MORE: Reading FC defender on verge of Portsmouth move in cut deal

With just eight minutes of action since September, it remains to be seen the impact his potential exit could have on Ruben Selles' side.

However, there are a few players whose impact would be unquestionable should the Royals be unable to keep hold of them.

Let's take a look at three regulars that the club will be desperate to cling on to come Friday morning.

Sam Smith

Making an emotional return to Berkshire over the summer after a few years of finding his feet in the lower leagues, the Academy graduate signed a three-year contract from Cambridge United.

Injured when he first arrived, it took the centre-forward until October before he got on the pitch and November before getting on the scoresheet.

However, a run of six goals in nine matches over the festive period helped propel the club back toward safety, grabbing plaudits for his energy and hold-up play despite getting little in the way of clear-cut scoring chances.

On a run of over 500 minutes without a goal, the 25-year-old remains crucial to the way the Royals play and has built up a strong rapport with the supporters.

Harvey Knibbs

A good friend of Smith's from their days at Cambridge, the duo arrived together and have been inseparable since.

Not fitting in at the start of the season with a 4-2-2-2 formation, the 24-year-old has become crucial in the 4-3-3 switch and is now the top scorer.

Hitting 12 goals in all competitions, including a hattrick against rivals Swindon Town, his non-stop running and pressing has made him a key cog in Selles' machine.

Match this with a likeable and infectious personality, the midfielder is vital if the Royals has aspirations of remaining in League One this season.

Femi Azeez

An Academy graduate out of contract in the summer, it has surprised a few that the 22-year-old forward is still in Berkshire this late on in the month.

On the receiving end of some frustrations early on in the season for his wastefulness in front of goal, he finally got off the mark in a 5-1 win over Carlisle United in November.

This kickstarted a run of six goal contributions in eight matches as the Royals began to head up the third-tier table.

Still yet to find his consistency, the pacey wide man has made himself one of the first names on the team sheet and would be hard to replace if a club were to prise him away from the club that gave him his start in the professional game.