NEW YORK (Reuters) - Major League Baseball and the players' association are seriously considering realigning its leagues to have 15 teams each, with one National League club moving to the American League, according to an ESPN report on Sunday.

MLB and the players' association are in talks over a new labor agreement and besides realignment, Commissioner Bud Selig has said the possibility of adding teams to the playoff structure is also on the agenda.

The National League has 16 teams and the American League has 14, with both leagues comprised of three divisions.

Currently, division winners reach the postseason along with a wildcard team from each league that has the best record outside its division champions.

According to a highly-ranked executive, one proposal raised in ownership committee meetings was eliminating divisions altogether, so that 15 AL and 15 NL teams would vie for five playoff spots within each league, ESPN reported.

A source who has been briefed on the specifics of the labor discussions told ESPN that the players' union indicated that it was open to the idea, but that the plan had not been presented to all the owners.

One of the biggest issues that would need be resolved in a realignment resulting in two 15-team leagues is which National League team would switch to the American League.

Two top executives believe the Houston Astros would be a possibility, because such a switch would foster a rivalry between the Astros and the Texas Rangers, the network said.

(Writing by Larry Fine, Editing by Frank Pingue)