It’s more of a sliding scale from “larger” to “smaller”. Portland is on the “smaller” end of the scale. But there’s no magical cut off number that makes a market large.

Rank Metropolitan Area Metropolitan Division State(s) Population
1 New York–Northern New Jersey–Long Island NY–NJ–PA 18,815,988
  
2 Los Angeles–Long Beach–Santa Ana CA 12,875,587
  
3 Chicago–Naperville–Joliet IL–IN–WI 9,524,673
  
4 Dallas–Fort Worth–Arlington TX 6,145,037
  
5 Philadelphia–Camden–Wilmington PA–NJ–DE–MD 5,827,962
  
6 Houston–Sugar Land–Baytown TX 5,628,101

7 Miami–Fort Lauderdale–Pompano Beach FL 5,413,212
  
8 Washington–Arlington–Alexandria DC–VA–MD–WV 5,306,565
  
9 Atlanta–Sandy Springs–Marietta GA 5,278,904

10 Boston–Cambridge–Quincy MA–NH 4,482,857
  
11 Detroit–Warren–Livonia MI 4,467,592
  
12 San Francisco–Oakland–Fremont CA 4,203,898
  
13 Phoenix–Mesa–Scottsdale AZ 4,179,427

14 Riverside–San Bernardino–Ontario CA 4,081,371

15 Seattle–Tacoma–Bellevue WA 3,309,347
  
16 Minneapolis–St. Paul–Bloomington MN–WI 3,208,212
17 San Diego–Carlsbad–San Marcos3 CA 2,974,859
18 St. Louis MO–IL 2,803,707
19 Tampa–St. Petersburg–Clearwater FL 2,723,949
20 Baltimore–Towson MD 2,668,056
21 Denver–Aurora CO 2,464,866
22 Pittsburgh PA 2,355,712
23 Portland–Vancouver–Beaverton OR–WA 2,175,113
24 Cincinnati–Middletown OH-KY-IN 2,133,678
25 Cleveland–Elyria–Mentor OH 2,096,471

Out of the top 25 metro areas in the US, Portland is No. 23. MJ’s number. Lebron’s as well!

http://en.wikipedia.org/wiki/United_States_metropolitan_area

being able to sell out those suites and create a demand for them helps the team. Also ‘large’ can mean number of people attending the game, and number watching on TV. Just becasue we are on national tv a lot doesn’t mean we get the same number of viewers as a LA or Boston game. You could also add number of newspapers and TV stations that cover the team. A lot of it also has to be national perception and east coast bias. When people think of th ewest coast they thing of LA, San Fran, and Seattle. Portland doesn’t have a big enough appeal

When they talk about market size the defining factor is the population of the surrounding metro area. This skews against Portland IMO because rarely does the affect of other teams in the area come into play and Blazer fans span the ENTIRE PNW (especially w/ Seattle out of a team).

http://www.forbes.com/sportsbusiness/2008/12/03/business-basketball-nba-biz-sports-nba08-cz_kb_mo_cs_1203intro.html

The city (= ability to fill a large arena + sell a lot of merch) has a lot to do with it, in some cases more so than the quality of the team. NY, LA (Lakers), Chicago, Detroit, Cleveland (that would probably be helped a lot by the LeBron effect), Houston, Dallas, Phoenix, Boston (they don’t own their arena), San Antonio, Toronto, Miami, … Portland is #20, which is a big improvement in recent year and in fact they made the largest jump in value last year. I think Utah might be the best-ranked small-market team, at #14.

Another factor to attract free agents: Taxes, which benefits Miami and Orlando (and the climate, which also benefits Phoenix).

P.S.: I think the chance to attract LeBron is fairly small, since he is NOT all about winning titles