Boyd confirmed yesterday he has agreed a two-year deal with the Coca-Cola Championship club, whom ex-Celtic forward McDonald signed for in February.

The pair may be used to being on opposite sides of the Old Firm divide but MacDonald admits he is intrigued to see whether the pair can operate together at the Riverside.

"It's an odd combination, an ex-Rangers player and an ex-Celtic player," he said. "Scott likes to run about, rather than just staying through the middle.

"He scored a lot of goals and he worked for his goals, whereas a lot of people would say Kris is a poacher.

"I think they will be a good combination if they can get a run going and get a few goals early in the season.

"Scott found it hard moving down there and hasn't scored a lot of goals so it will be interesting to see if Gordon Strachan is going to be able to blend them together."

MacDonald added: "He (Boyd) has done a lot at Rangers. I don't think anyone could complain about the goals he has scored for Rangers and he has been brilliant for them.

"Rangers fans are going to think it's a step back to leave Rangers for the likes of Middlesbrough.

"But the Championship seems to be a very hard league now. It's so competitive and there is big money down there.

"The top teams there are paying big bucks to get the players that will get them into the Premier League.

"I think Middlesbrough have a good chance and they have a strong enough squad to challenge this year, at least to get into the play-offs anyway."

Boyd's potential switch to Boro means any lingering hopes of the striker making a dramatic U-turn and remaining at Rangers after all have been dashed.

And MacDonald expects the Scottish champions to now begin making moves of their own in the transfer market.

The Ibrox side have secured their management team on new deals, as well as defenders Kirk Broadfoot and David Weir, but boss Walter Smith has yet to recruit any new personnel.

"Walter will probably have a few players in mind who he wants to sign but he's very coy about who he does like," said MacDonald.

"There's not been much in the press about who Rangers are after.

"He will have to strengthen the squad as a few of the fringe players have left, as well as Boyd.

"He has a strong enough squad but Walter will want to pick up one or two guys who will play regularly and do a job for him."