Talks are heating up involving Cuban star Rusney Castillo, and it's a good thing because he has designs on playing in the big leagues this season, according to people familiar with his situation.

There is said to be urgency on the part of some of the teams involved in talks, and that makes sense since at least two teams known to be in the running -- the Tigers and Giants -- could use him in the pennant race. The Tigers have been known to be heavily in the mix, while Ken Rosenthal of Fox Sports first mentioned the Giants as a potential player.

Castillo, who's seen as an impressive blend of speed and surprising power, also has drawn interest from at least the Red Sox, Phillies, Yankees, Cubs and Mariners. There are said to be at least four teams still in the running, with the Red Sox also known to be among those teams, though it isn't certain which of the other teams still is.