From SABR Encyclopedia
A ballpark is any location where baseball is played. A ballpark meets the notability requirement if it has hosted at least one Major League game, Negro Leagues game, or minor league game. College ballparks may meet the notability requirement if they are a dedicated facility used by a college team for a significant span of time.
 Page naming and disambiguation
When possible, the page name for a park should be the full name the park was most commonly known as. A judgment call may be required if the park has been known by multiple names. For parks with corporate-sponsored names, there is no fixed convention as to what the main name, and therefore article title, should be. If a park has been known by more than one name, redirect pages should be created for the alternate names. For instance, Enron Field redirects to Minute Maid Park.
When more than one park with the same name has existed in the same locale, Roman numerals I, II, III, etc. are used to distinguish the various incarnations; see, for example, the five incarnations of Polo Grounds in New York. When parks by the same name have existed in different places, disambiguation is done by adding the city and state in parentheses. The disambiguation page for League Park is a good example of how to do this. In either case, disambiguation pages should be created, or new entries to an existing disambiguation page should be added.
As a rule, if there is one Major League park by a given name, it should be the main article, i.e., the article on the page without any parenthetical disambiguation. An example of this is Memorial Stadium; the park in Baltimore is clearly the most prominent Memorial Stadium, so it is located as the main article, while other parks name Memorial Stadium are organized at Memorial Stadium (disambiguation). If there are multiple Major League parks known by the same name, or multiple minor league parks and no Major League park, the general policy is for the main article to be a disambiguation article; see League Park.
A park may have a page even if we do not know its official name, as long as it is known to have existed, meets the notability criteria, and we know some facts about the park (such as its capacity or location). These parks should be referred to as "Unknown Park," disambiguated by the city they are located in. See Unknown Park for the main disambiguation page covering these parks.
All ballpark pages should contain an instance of Template:park-infobox containing the basic information about the park. The presence of this infobox is used by automated programs to construct queryable lists of ballparks.
The templates Template:park-occupants-start, Template:park-occupied-by, and Template:park-occupants-end are used to construct a formal list of teams which have used the park as a home park. This includes alternate site and other one-off games. The Template:park-occupied-by template also automatically creates a link internally with the pages corresponding to the teams. When creating these records, take care to be sure the team is referred to by the same name as it is referred to on its page (the team's "short name"). See, for example, Phil Welch Stadium, and note the separate record for the St. Joseph/Carthage team, which relocated in the middle of the 1941 season.
A good technique to make sure the club references are correct is first to preview changes before saving. At the bottom of the preview screen is a fact box. Look at the list of club pages generated; if any of the links are red, this indicates the page reference is not correct.