Has Celtic's decision about Stuart Armstrong's future just got easier?

Premier League side Southampton are keen on Stuart Armstrong, but Scottish Premiership giants Celtic simply must keep him.

James Forrest of Celtic celebrates his goal (Celtics 1st)with Stuart Armstrong during the Betfred Cup Final at Hampden Park on November 26, 2017 in Glasgow, Scotland.

Stuart Armstrong was arguably the best midfielder in Scottish football last season but, ever since that protracted contract saga over the summer, he has struggled for form.

The 25-year-old has just five goals in 35 games in all competitions this time round; a far cry from the 17 he managed across 2016/17. And it is not just his ability to find the net but his overall game which appears to have dropped a level since those summer links with the likes of Southampton.

Nonetheless, Armstrong will still be welcomed back with open arms as Celtic prepare for a daunting Europa League clash with Zenit St Petersburg. The Scotland international underwent a hernia operation in mid-January and is expected to return ahead of schedule as Brendan Rodgers prepares to put his wits against Roberto Mancini.

Stuart Armstrong of Celtic in action during the UEFA Champions League Qualifying Second Round, Second Leg match between Celtic and Linfield at Celtic Park Stadium on July 19, 2017 in...

Celtic have hardly thrived in Armstrong’s absence and his dynamic, forceful presence in the centre of the park was badly missed in Saturday’s dire 1-0 defeat at Kilmarnock.

A shock loss at Rugby Park means Celtic are now 16 points worse off than they were at this stage last season, but it was not just the result but the nature of the defeat which should concern supporters. The Hoops didn’t manage a shot on target until the last minute.

And while Armstrong has not been himself of late, it is worrying to see just how toothless and one-paced Celtic looked without him in their starting XI. In truth, there is no other midfielder in Celtic’s squad capable of changing a game like the former Dundee United man, evidenced by their blunt approach at Killie.

Stuart Armstrong (L), of Celtic celebrates scoring a goal early in the first half with team mate Kieran Tierney during the William Hill Scottish Cup Final between Aberdeen and Celtic at...