CELTIC can't teach an old dog new tricks, but they can pay one to keep delivering the ones he knows.

No discourtesy is intended towards 31-year-old Kris Commons, but all the uncertainty which surrounded his future at Parkhead was over an issue relating to his age.

Celtic were hesitant about giving him the length of contract he wanted - another two years - because he would be almost 34 by the end of it. Commons's refusal to sign for only one more year had led to an impasse which seemed likely to end in his departure as a free agent this summer. The club and player continued to talk, though, and yesterday a breakthrough was announced. Commons has signed to stay until the summer of 2017.

The development came as a surprise to those who had detected the obvious strain in the player's relationship with the club. He had thrown his boots into the travelling support when Celtic won at Hamilton last month, interpreted by many as a farewell gesture from a midfielder who had a major influence since joining in January, 2011.

When Commons then took it upon himself to speak to the medi about his contract situation after a game at Ross County, without Celtic's permission, that was also taken as the actions of a man trying to force the club's hand. On the other side, manager Ronny Deila had frequently stressed Commons's importance to the team but had hinted, too, that there was reluctance to commit to longer contracts for players over 30.

The arrival of midfielders Stuart Armstrong and Gary Mackay-Steven, and the certainty that Scott Brown and Stefan Johansen will have key roles to play in the centre, means Commons will face continued competition for midfield places from Anthony Stokes, Charlie Mulgrew, Nir Bitton, James Forrest, Callum McGregor and Liam Henderson, among others. But there was pleasure all round that a deal had been struck.

"I'm absolutely delighted to have signed this new contract with the club," Commons told the Celtic website. "I've loved my time at Celtic and this is where I want to continue playing my football. The club is in a great place, we're still in four competitions this season and already have a cup final to look forward to, and I want to continue playing my part in bringing more success to the club. I'm also delighted to continue playing in front of these magnificent fans, who have been brilliant with me and my family from the day I joined Celtic."

Deila did not always start Commons in big games early in the season but already there have been 28 appearances in the current campaign, in which he has scored eight times. His total figures stand at 74 goals in 176 games for Celtic.

"I am really pleased that Kris has committed his future to the club," said Deila. "I am sure he will continue to be a very important player for us as we work hard to bring our fans the success they deserve. We have had a good week after reaching the League Cup final and following the fantastic signings of Stuart Armstrong and Gary Mackay-Steven, Kris's contract extension is even more great news for the Club and our supporters."

Only one Celtic supporter was disappointed by the outcome: Neil Lennon, the former manager, who had hoped to take Commons to Bolton.