UPDATE, 6:32: The Rays have signed the Polonius twins from Curacao – Ryson and Rainer, 16-year-old lefty-hitting shortstops. Ranked Nos. 30-31 by Baseball America.

DEVELOPING: The Rays, as usual, are active with Monday's opening of the international signing period, agreeing to deals with three of the Baseball America's top 50 prospects.

SS Alejandro Pie, the No. 13 prospect, is a 6-4, 175-pound 16-year-old from the Dominican Republic described by Baseball America as "as an athletic shortstop with plus speed and a plus arm" who could project more as an outfielder. He agreed to sign for $1.4 million, per Jesse Sanchez of mlb.com.

OF Estanli Castillo, the No. 40 prospect, is a 16-year-old, 6-3, 195-pound power-hitting outfielder who is considered one of the top sluggers in the class, described as "big, strong and has plus raw power, blasting balls out of the park in BP with an uphill stroke" who puts on "a fireworks show" .in workouts but will need to make adjustments in games."

SS Daury del Rosario, ranked 50th, is another 16-year-old Dominican, listed at 6-0, 175 who is a switch-hitting shortstop who scouts like for "his hitting ability and track record of putting the barrel to the ball in games.''

The Rays also have agreements with these players:

Justino Dominguez, rhp, Dominican Republic

Brayan Dum, lhp, Venezuela

Jose Gonzalez, Dominican Republic.