Right-hander Cody Martin was optioned back to Triple-A Tacoma after pitching twice in the past two days since being recalled to take the place of Joel Peralta, who was designated for assignment on Thursday. Martin was the winning pitcher after throwing a scoreless sixth inning in Thursday's 16-13 victory over San Diego, then threw three innings with one run allowed in Friday's 7-3 loss to the Rangers.
Diaz has allowed just one unearned run with three hits, two walks and 16 strikeouts over 11 2/3 innings in 10 appearances since being converted to a reliever. Including six starts before being moved to the bullpen, he's 3-3 with one save and a 2.21 ERA in 16 games this year.
Diaz found out he was being promoted on Friday and called his family in Puerto Rico in time so that his parents, brother and sister and three friends were able to fly in for Saturday's game against the Rangers. His brother, Alexis Diaz, is a right-hander in the Reds organization who pitched in the Arizona League last year.
"I started smiling because this is a surprise for me," Diaz said of learning the news. "I feel very, very good to be here. I went out running with my teammates [before Friday's game] and I saw the field and said, 'Wow. I'm here right now.' This is a dream come true."
Diaz was a third-round Draft pick of the Mariners in 2012 out of Puerto Rico, and he was the club's Minor League Starting Pitcher of the Year last season after splitting time between Class A Advanced Bakersfield and Jackson, going 7-10 with a 3.82 ERA in 27 starts. But new general manager Jerry Dipoto and farm director Andy McKay saw a future with more upside as a reliever and that move appears to be paying immediate dividends.
"They told me a lot of positive things," Diaz said of the bullpen conversion. "They told me I could be in the big leagues quick. I set my mind to do my job. I didn't think it'd be this quick, but I was thinking this year I could make the big leagues with the team."
Diaz said he'll just keep doing what he's done since the club informed him his future appeared brighter in the bullpen.
"It's been good," Diaz said. "I like to win every time and I come to get outs. That's what I did in Double-A, get outs. Now I come here to do the same thing."
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.