It's technically a "Bullpen Rookie Goodie Bag," Leone said, and it's his duty to wear it when he makes his daily trek out of the clubhouse. Relievers Danny Farquhar and Yoervis Medina have one, too.
Where did the tradition come from?
"I guess it's an older guy thing," Leone said. "They designate the backpacks to all the younger guys."
It's fair to ask a similar question of Leone. Where did he come from? And why has he been so effective since being recalled from Triple-A Tacoma in early April? Leone finished 2013 in Double-A Jackson, and his numbers were solid, but didn't exactly indicate he was on a fast track to the Major Leagues. He was 1-2 with a 2.50 ERA in 18 innings after being promoted from Class A Advanced High Desert in July.
In seven appearances with the Mariners, the 22-year-old has a 1.69 ERA in 10 2/3 innings, including 10 strikeouts and four walks. The sample is small, but manager Lloyd McClendon said he sees in Leone a swagger that could eventually make him a late-inning reliever.
"I don't think any situation really overwhelms him, whether he's pitching late in the game or he's pitching in the fifth," McClendon said. "He's out there for one reason and he knows it, and he knows he's good."
Leone also goes after hitters and doesn't mind working with runners on base. He has a fastball in the mid-90s and the added benefit of being new to the league. After all, the 5-foot-11, 210-pound righty began last season with Class A Clinton of the Midwest League.
"It does help that these guys haven't seen me before and maybe the scouting report isn't as in-depth as some of these other guys, but I think just going out and attacking and being consistent is really my strong suit," Leone said.
Where does the confidence come from?
"You've just got to keep telling yourself that you belong here," he said. "You've got to trust your ability, trust your talent. It also helps having guys who just are constantly behind you. All these guys during Spring Training, they're always backing me. That gives you confidence. It's like 'Wow, these guys believe in me. Why would I not believe in myself?'"
Mike Zunino is among the converted.
He said he first caught Leone in 2012 when the pair played Class A Short Season for Everett. He was impressed then and he's impressed now.
"I think he just attacks hitters," Zunino said. "He's got great power stuff, and he attacks the strike zone with his fastball and cutter and then he has his slider late in the count."
Leone grew up in Norwich, Conn., then went on to a three-year career at Clemson, earning co-captain honors during his junior season. In 2012, the Mariners selected him in the 16th round of the First-Year Player Draft. After splitting last season between Short A, High Desert and Double-A, he was a non-roster invite to Spring Training. He pitched well enough to earn a spot in Seattle's bullpen, posting a 1.80 ERA and holding opponents to a .171 batting average in nine appearances.
But veteran right-hander Hector Noesi was awarded the last long-relief spot. The reclamation attempt failed less than a week into the season. Noesi was designated for assignment the day after giving up a walk-off homer to Oakland's Coco Crisp in a 3-2, extra-innings loss April 3.
When Leone got recalled from Tacoma to replace Noesi, he had yet to appear in a game. Since, he's done nothing to temper expectations.
"You know, I've always said age is nothing but a number," McClendon said. "Experience is obviously one thing, but when you've got talent and you've got stuff and you're good and you know what you're doing, it really doesn't make a difference."
McClendon admitted that he's probably overused Leone early in the year. Still, when Leone gave up his first homer of the season Tuesday against the Astros, the Mariners' first-year manager said he was shocked.
"I guess he's human after all," he joked. "He's pretty dang good."
Especially for being "The Drink Guy."