The votes are cast by media members who cover the league. Paxton became the first Mariner to be named AL Pitcher of the Month since Felix Hernandez in June 2014. It's the first time Paxton has earned the award.
Diaz is the first to be named Reliever of the Month, an honor that began this season.
Paxton's July was impressive indeed. He became the first Seattle pitcher to win six games in any month, going 6-0 with a 1.37 ERA in six starts. Paxton racked up 46 strikeouts with six walks in 39 1/3 innings while holding opposing hitters to a .182 average and a 0.79 WHIP.
Paxton's monster month clearly showed that the 6-foot-7 lefty is fully back from a strained forearm that sidelined him for four weeks in May. He opened the year by going 3-0 with a 1.39 ERA in five April starts, but he was 2-3 with a 5.30 ERA in seven starts in May and June before he turned things around in July.
"It feels really good," Paxton said. "When I went out with my injury there, it took me a little while to get my legs under me and find it again. The July I had definitely made me feel like I'm back to where I was at the beginning of the season, feeling good and just back to where I need to be."
Paxton's strong month puts his season record at 11-3 with a 2.68 ERA in 18 starts. He is just shy of the innings requirement to qualify for the official league leaders list, with his ERA slightly ahead of leader Chris Sale's 2.70 for Boston. Paxton's next start is scheduled for Friday in Kansas City.
Diaz had a strong month as well, posting a 1.98 ERA with eight saves in nine opportunities while notching 21 strikeouts and five walks in 13 2/3 innings. Diaz's fWAR for the month -- 0.9 -- was the highest of any reliever in the Majors.
"It feels great," the 23-year-old Diaz said. "That's what I work for, trying to be the best. I work hard every day to help the team win, and I feel very happy that the team is winning and everybody is playing good. We're at a good moment right now."