Prospect watch

Gabriel Guerrero

Outfield, Class A High Desert

Signed as a non-drafted free agent in 2011 out of Nizao, Dominican Republic, Guerrero continues to hit for the Mavericks. On Thursday, he went 3 for 5 with a double and a home run while driving in a season-high five runs. The 20-year-old outfielder is hitting .310 (100 for 323) with a .803 OPS to go with 17 doubles, nine homers, 60 RBI and 13 stolen bases in 79 games. Guerrero will represent the Mariners on the World Team at the Futures Game at Target Field on July 13 as part of the 2014 All-Star Game.

Getting a call-up

Quinn Wolcott

Wolcott is staying in the big leagues for good. Major League Baseball announced on Friday that Wolcott has been moved to a full-time major-league umpiring staff. The Puyallup native and Emerald Ridge grad has been working between Class AAA and the big-league level this year. He made his MLB debut on May 13, 2013, and has worked 149 big-league games. At 28, he is the youngest full-time umpire in MLB. He will work on the umpiring crew that is led by Gerry Davis.

Wolcott replaces veteran umpire Gary Darling, who is retiring after 28 years in the big leagues. Darling has been injured and has not worked a game this season.