SEATTLE -- Scott Servais made a promise to Edwin Diaz early in the season. If the young Mariners closer gets to 50 saves this season, Seattle's manager will get his hair cut in the same style as Diaz, including the shaved sides.

It seemed a safe bet at the time, given only 16 closers in baseball history have reached 50 saves in a season. But here we sit on June 13, just 40 percent of the way through the season, and Diaz has already cranked out 25 saves and is on pace for 60, just shy of the MLB record of 62 by Francisco Rodriguez of the Angels in 2008.

"I'm aware," Servais said with a smile, touching the sides of his head. "Guys are starting to talk about barbers and things like that. I'm OK with that."

The hard-throwing 24-year-old has put up some amazing numbers in helping push the Mariners to one of the best records in the American League. With 25 saves and 58 strikeouts in the team's first 67 games, he's two strikeouts short of becoming the first AL closer ever to notch 25 saves and 60 strikeouts by the All-Star break.

And the All-Star break is still a month away.

The Mariners record for saves by the All-Star break is 29 by Kazuhiro Sasaki in 2001, when Sasaki became the only Seattle pitcher to lead the Majors in saves at the break (he was tied with Mariano Rivera). The only other Mariner with more saves at the break than Diaz's 25 was Fernando Rodney , with 27 in '14.

Diaz likely won't touch the MLB record of 38 saves at the break, set by the Angels' Rodriguez in his historic 2008 season, but Rodriguez didn't have the strikeout numbers of Diaz, as K-Rod only totaled 77 for the entire season that year.

Diaz has been dominant, even in the toughest of situations. When entering a game with a one-run lead, he's recorded 15 of 17 saves with a 1.04 ERA, 31 strikeouts and four walks while allowing just two runs in 17 1/3 innings. The Mariners are 17-0 in those games.

The downside of playing so many tight games is Diaz is being used more heavily than hoped. Servais said he'd give the youngster the day off in Wednesday's series finale with the Angels, having pitched the previous three games and four of the last five.

"He's been very efficient," Servais said. "But we have to be smart. You see it a little when you start wearing him down. Fortunately, he hasn't had a lot of those 20-25 pitch innings. The pitch numbers have been low, but we want to be smart on this thing. We have a lot of ballgames left to play. But he's been very, very good."

With an upper-90s fastball and a nasty slider, Diaz has struck out 42 percent of the batters he's faced (58 of 138) and opposing batters are hitting just .156 against him. He stuck strictly with heat in his 1-2-3 ninth against the Angels in Tuesday's 6-3 win, until whiffing Michael Trout with a two-strike slider that left the Angels' star shaking his head.

"You've seen more fastballs out of him lately and that's been by design," Servais said. "It's helped get a feel for the slider. When he's throwing the fastball and locating it, certainly to glove side, his hand gets out front and the slider is way more effective."

And an effective Diaz could lead to a new hairstyle for his skipper if he continues to roll.

Worth noting

• Third baseman Kyle Seager was a late scratch from Wednesday's game to deal with a personal family issue. Utility man Andrew Romine started in his place.

• Nick Vincent (strained right groin) will likely throw a bullpen session on Friday or Saturday after having his Monday mound session halted midway by continued soreness. Juan Nicasio (swollen right knee) is also slated for a bullpen session on Saturday.

Servais said both relievers could be ready to come off the 10-day disabled list midway through the next road trip in New York or Boston next week.

Reliever Dan Altavilla is not close to returning from his strained right forearm, as he's expected to be shut down from throwing for the next month or so.

Greg Johns has covered the Mariners since 1997, and for MLB.com since 2011. Follow him on Twitter @GregJohnsMLB.