Every year, UEFA makes any club who wants to take part in European competitions apply for a UEFA club license. Without the license, you can’t take part in either the Champions League or Europa League. As part of the review process, UEFA looks at a club’s accounts to make sure they are sound budget wise to handle a season in Europe. The application deadline for this year was March 1st.
On March 9th, the Portsmouth News reported that Portsmouth FC decided not to apply for a UEFA license. That decision was made because, according to the article, the club were not in a position to submit its accounts to meet UEFA criteria. They still had the option to apply even while in administration, but opted not to.
So, in the end, Portsmouth FC decided a month ago to not bother with an UEFA license, and so can’t go to the Europa League now.
Given Chelsea will most likely make the Champions League, that means 6th (or 7th considering Manchester United won’t be using their spot for winning the Carling Cup either) is now going to be enough for the Europa League.
According to Bert Kassies’ unofficial European Cup football site, there were four teams who would have made European competitions this year but did not get UEFA club licenses, including one domestic cup winner. So while not common, it’s not totally unheard of.