Celtic manager Gordon Strachan insists his decision to block Jim O'Brien from playing against the Parkhead side in the Tennent's Scottish Cup final was simply "common sense".

The 19-year-old midfielder was loaned to the Pars by the Bank of Scotland Premier League champions in January and helped knock Rangers out of the tournament in his first game for the Fifers.

O'Brien played against Hearts, Partick Thistle and Hibernian in the following rounds but will have to sit out the showpiece occasion at Hampden Park on May 26.

However, Strachan insisted there was never any chance that the Hoops' youngster would turn out against his employers.

The Celtic boss explained: "The agreement was Jim couldn't play against us at all this season.

"Stephen Kenny phoned me yesterday asking about Jim's availability and I said the agreement still stands which is unfortunate for the player.

"The first person I called after that was Jim and he was very philosophical about it and I think he was expecting that decision.

"Hopefully he can keep improving and get himself to more cup finals.

"It wouldn't have been an easy thing for Jim, or for us, for him to play.

"Jim is a Celtic player and there are all sorts of things that can happen on a football field.

"You can get involved in controversies or score winning goals so it was a problem.

"It wasn't an easy decision to take but the more we thought about it, it was only common sense.

"I don't think anyone at all at Celtic or any football club would say it wasn't the right decision because the priority is to win trophies."

Strachan, recovering from a hip operation carried out last Wednesday, believes he has stolen a march on his SPL rivals by adding Scott Brown and Scott McDonald to his squad for next season before the current campaign has ended.

Scotland midfielder Brown was signed this week from Hibernian for a record fee between two Scottish clubs believed to be in the region of £4.4million while the Motherwell striker will also arrive in the summer.

The former Coventry and Southampton boss said: "Hopefully we will give Scott Brown and Scott McDonald the platform to go and improve on the good work already done at their previous clubs.

"I don't know how many clubs we beat to get Scott (Brown), I just know that we made him a priority and he's here.

"I've got two players I want. You can't get everything in life but I'm happy so far.

"You don't want to be scrambling about at the end of July because that can cost you.

"We've done our homework and hopefully it's good business for the club."

Strachan is continuing his interest in Borussia Monchengladbach midfielder David Degen.

The Switzerland midfielder, 24, who is only a third of the way into a three-year contract with the German club, was criticised by his coach Jos Luhukay for being a disruptive influence on team-mates at training.

But Strachan said: "He's away back to his club today.It's good that he can come to see us and we can see him and get to know what we are dealing with.

"I think he has enjoyed his few days here and we took him to the UEFA Cup final with us.

"We will have to sit down and talk about it but the first person to know about it will be David."