"He's a good player," Mariners general manager Jerry Dipoto said. "He's done what you can do in Triple-A and deserves an opportunity. He does a lot of things well. He plays all three outfield spots. Everything about his game from a tool perspective is average to above.
"The one thing he doesn't bring is gaudy power, but it's a contact, gap bat. He can steal bases. He's a nice piece for us. He's optional, young and athletic -- a lot of the things we've talked about since last September."
The left-handed-hitting outfielder played six games with the Yankees in May, going 1-for-8 with one run and one walk while playing mostly as a defensive replacement. The Mariners have been looking to get more athletic in the corner outfield positions defensively, and Dipoto said Gamel will be given a chance to contribute in the final month.
"That's the idea, for him to chip in," Dipoto said. "We'll see where he is in September and what that means for 2017. He's a polished Minor League player who is ready to cut his teeth in the big leagues."
Gamel was Rookie of the Year for the International League in 2015 after hitting .300 with 77 runs, 64 RBIs and 13 stolen bases in 129 games. He was selected by the Yankees in the 10th round of the 2010 MLB Draft out of Bishop Kenny High School in Jacksonville, Fla.
The Mariners gave up a pair of young right-handed pitchers, Jio Orozco and Juan De Paula.
De Paula, 18, was 1-2 with a 3.07 ERA in 11 games, including seven starts with the Arizona Rookie League Mariners this season. Orozco, 19, was 2-2 with a 4.07 ERA in 12 games, five starts, with the same club.
"Both are long-term projection type guys," Dipoto said. "Both have shown power stuff at times, but obviously need the consistency that needs to come with going through the long developmental process. Both have Major League potential, and we'll see where they go."
Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.