Jupp Heynckes thrust David Alaba into the left back position basically as a stopgap last season. As we all know, Alaba grew into the position and emerged as quite a good defender. In fact, you can easily make the argument that for the 2012-2013 European season, Alaba was the best left back in the world.
However, whenever the 20 year old suits for Austria, he is always playing in the midfield. While he will play in the midfield for Bayern from time to time, that part of the field is crowded right now with players fighting to get more playing time. Since being promoted to the Bayern first team, Alaba has played wherever he's been needed whether that's left back, central midfield, left attacking midfield, right attacking midfield, or central attacking midfield.
What position does Alaba prefer? He told the Austrian newspaper Kurier (Note: I can't find the article on Kurier's website, but here is the report from TZ.) that he saw himself as a central midfielder, and his goal was to play in the midfield for Bayern one day.
Now, reports from Salzburg.com and Sport Bild suggest that Arsenal are interested in bringing Alaba to the Emirates Stadium. They suggest that Arsene Wenger will try to lure Alaba to London with his desire to play in the center of midfield.
Important thing to know: Alaba is under contract with Bayern Munich through 2015.
While we don't exactly know what Pep Guardiola plans to do with Alaba, it is difficult to imagine the Austrian cracking a starting central midfield position. Bastian Schweinsteiger and Javi Martinez have those two positions on lockdown while Luiz Gustavo is an excellent backup to the two.
For Bayern, Alaba's best position for the club to be successful is at left back. For Austria, Alaba's best position is in the center of midfield, and he's recently said that he would prefer to play in the midfield. What does this all mean? Nothing really. It would absolutely blow me away if we saw Alaba playing in London instead of Munich in August. However, if Alaba continues to prefer playing in the midfield to defense, you can't rule out a potential transfer in the future. For now, let's enjoy Alaba wearing the Bayern shirt.