It's fair to say that it has been a worrying few days for Arsenal fans. First, captain Robin van Persie was sold to long-time rivals Manchester United just a day before the Gunners kicked-off their Premier League season with a disappointing goalless draw at home to Sunderland.

Now, midfielder Alex Song is also waving farewell to the Emirates as he gets set to be presented as a Barcelona player. The Press Association reports that the Cameroonian midfielder has passed a medical with the Catalan giants to finalize his £15 million move.

While Song led Arsenal in assists last season, the Daily Mirror has speculated that manager Arsene Wenger may not be too disappointed to lose the 24-year-old. According to the story, Song was allowed to leave after "he continually turned up late for training, was seen as being lazy, drove the coaching staff to distraction and lacked defensive discipline."

Certainly Wenger hinted that there were various factors at play in Song's departure.

"There are different reasons, I don't want to come out with that now, but it happened," he said. "Every case is individual and maybe one day I will explain everything."

There is no doubt that, for all his qualities, Song often went missing up field leaving crucial gaps for the opposition to exploit. A more disciplined holding midfielder may now be brought in to replace Song.

Wenger confirmed that he is looking to reenter the transfer market.

"We are looking to bring one more midfielder in of course, and maybe one defender as well because we still feel we are short in some positions," he told Arsenal Player.

One man that now looks all but certain to arrive is Real Madrid midfielder Nuri Sahin. The Daily Telegraph reports that the Turkey international has verbally agreed to join the Gunners on a season-long loan ahead of strong interest from Liverpool. The move is set to cost Arsenal £2 million.

The 23-year-old struggled for first-team football last season at the Bernabeu following his move from Borussia Dormund.

With Sahin being more of a playmaker than a defensive midfielder, there is still speculation that Wenger may seek to bring in more of a direct replacement for Song.

Arsenal could be set to reignite their interest in Anderlecht midfielder Lucas Biglia. The Gunners are one of several big clubs to have been linked to the Argentina international, who has now confirmed that he is available this summer.

"I can leave for €8million in the current market, and that is quite a lot of money--but I agreed to this transfer fee myself so I can't really complain," he said, according to Sky Sports.

"There are clubs ready to pay that amount but they are not better than Anderlecht so for now I focus on this club. I want to at least be playing in Europe.

"I think we could really do something in the Champions League too this year. So there are many challenges left here."

In terms of strengthening the defense, there is renewed speculation that Arsenal could move for France international Philippe Mexes. According to the Sun, the 30-year-old could arrive at the Emirates from Milan in a swap deal with Arsenal forward Nicklas Bendtner.