B.J. Upton might not be Carlos Beltran, but he’s rapidly emerging as a potential alternative for teams in the Beltran sweepstakes.

The  Giants, while continuing to pursue Beltran, also are showing interest in Upton, according to major-league sources.

Upton, 27, would be a logical fit for the Giants, upgrading their offense and providing strong defense in center field behind the National League’s top pitching staff.

Beltran, 34, is a superior offensive force to Upton, but his full no-trade clause and pending free agency make him more problematic as a trade target.

Upton can be obtained without restriction and is under club control through next season. The Giants and other clubs likely would be more willing to sacrifice prospects for a player they could keep for another year.

The Indians, a team that showed early interest in Beltran, also is pursuing Upton, sources say. Several other suitors for Beltran - the Braves, Phillies and Rangers – also could target Upton.

The Giants are using Nate Schierholtz as their primary right fielder. The addition of Upton would give the team three outfielders – Upton, Andres Torres and Cody Ross - for two spots.

Ross, a right-handed hitter, could platoon in left with Torres, a switch-hitter who has been much stronger from the left side this season. Torres plays all three outfield positions. Upton has played center almost exclusively in his career.

Playing for the defending World Series champions at sold-out AT&T Park could energize Upton, who occasionally has drawn criticism for his seemingly disinterested play in Tampa Bay.

Upton also could be motivated by playing in the same division as his younger brother Justin, who is the right fielder for the Arizona Diamondbacks.

-Ken Rosenthal and Jon Paul Morosi