McAllister took advantage of United's conclusive 2-0 lead over Walsall to involve Douglas in the final eight minutes of Saturday's match, more than three months after the midfielder's last appearance for the first team.

The sight of Douglas stepping from the bench prompted a standing ovation from the crowd at Elland Road and signalled the end of his struggle against the knee ligament injury he sustained at Walsall's Bescot Stadium on December 15.

McAllister said the Republic of Ireland international would have a "big part to play" in the remainder of United's League One season, but his determination to utilise Douglas is being tempered by the desire to keep faith with the players who are already in possession of the four midfield positions in his line-up.

United's manager has maintained a midfield of Neil Kilkenny, David Prutton, Jonathan Howson and Bradley Johnson for the past five games, and Saturday's comfortable victory over Walsall was produced by as complete a performance as McAllister has seen from Leeds.

The 43-year-old said: "There are 10 midfielders here and we've got a quality bunch for this level of football. I'm obviously disappointing a few of them.

"The four who are in possession at the moment are going to be hard to shift if they keep this form going, but I'm sure Jonathan has got a big part to play from now until the end of the season.

"He's been wanting to be in and around the squad and now he's back it's a big plus for us."

Douglas and Andrew Hughes, who missed Saturday's game through suspension and is halfway through a two-match ban, are the two players most likely to infringe on the present midfield set-up and United's strength in depth may prove valuable during a busy schedule through April.

The month has been crowded by rearranged fixtures against Doncaster Rovers and Huddersfield Town, who Leeds were originally due to play this evening but will now visit on April 15, and the availability of Douglas is a particular bonus after an injury which United initially expected to end his season.

The midfielder began his comeback with a gentle practice match at Leeds' Thorp Arch training ground and put himself in contention for a first-team recall by completing 90 minutes of last week's reserve game against Sheffield Wednesday.

McAllister said: "He's been champing at the bit for a while now, and it was just a case of holding him back.

"We set up a controlled game at the training ground and advised the youngsters not to go in and kick him. I then surrounded him with quite a strong reserve side in Sheffield, rather than asking him to play with kids. He showed up well."

More satisfying for McAllister than Douglas' return, however, was the production of a clean sheet against Walsall, seven days after Leeds had conceded three goals at Port Vale.

United's central defensive pairing of Lubomir Michalik and Rui Marques displayed a level of understanding and cohesion which had been missing during the past month, and the inclusion of Alan Sheehan at left-back – his first outing since the 1-1 draw with Crewe Alexandra on February 23 – was also a success.

The young defender was signed in January on loan from Leicester City until the end of the season, but he appeared to struggle with the immediate transition from the reserves at the Walkers Stadium to the first team at Elland Road.

A programme of additional work on the training ground has helped Sheehan to meet the standard required by McAllister, and United's boss said: "I was pleased for Alan.

"He arrived here and it was clear after a couple of games that the jump from reserve-team football and inactivity to first-team football was just a bit too much for him.

"But he's buckled down and worked extremely hard, doing a lot of work in the afternoons. I thought he played well.

"As much as I was pleased with the forward play and the stuff in the final third (against Walsall), after conceding three at Port Vale I thought we defended really well.

"We held a much stronger line, and I felt the two centre-halves headed more balls in 90 minutes than they have done in the seven or eight games that I've been here. The clean sheet was the most important thing."

Saturday's victory over Walsall earned McAllister's players a short period of leave from the training ground for what may be their final break before the end of the season.

Leeds host Brighton on Saturday and will then play seven matches in the space of 33 days, concluding their campaign at home to Gillingham on May 3.

McAllister said: "Coming in after a period of time out, I'm obviously nice and fresh to it all.

"But I've got to sit back and take stock of the fact that these guys have played 38 games.

"It's maybe an opportunity to give them a few days off and let them spend a bit of time with their families."