Scan the A's bullpen right now. There's a veteran trying to show he belongs as closer. And there are four unproven pitchers just hoping to show they belong in the majors.
You want the "X" factor for the A's this season? Follow the fortunes of their relief corps.
"We just need to go out and get the job done," left-handed set-up man Brian Fuentes said. "It's not about proving something to anybody. It's about going out and throwing zeros up."
The A's bullpen allowed 33.7 percent of its inherited runners to score in 2011, the fourth-highest mark in the American League. More consistency is needed, and the A's are trying to accomplish that without two-time All-Star closer Andrew Bailey -- traded in the offseason to Boston -- and without right-hander Joey Devine, who underwent season-ending elbow surgery Tuesday.
As the A's begin a seven-game trip Friday in Seattle, one of their biggest questions remains how Grant Balfour will adapt as the new closer.
So far he's converted both his save opportunities, and he threw two scoreless innings in Wednesday's 5-4, 12-inning victory over Kansas City.
But the eight-year veteran entered this season with no full-time experience in the ninth inning, and some of his numbers from 2011 raise red flags. The fiery Australian posted a 2.47 ERA and held opponents to a .199 batting average, but he blew five save opportunities and allowed homers to the first batter he faced four times.
Fuentes has closed before -- he had a major-league leading 48 saves for the Angels in 2009, and his next save will be the 200th of his career -- but the A's would be happy if he is a reliable left-handed set-up man. Last year, he went 1-8 with a 5.09 ERA over his first 38 appearances, and on Wednesday he allowed a seventh-inning, game-tying homer to the Royals' Alex Gordon.
But Balfour and Fuentes appear to share an important responsibility -- guiding the A's inexperienced stable of relievers. Andrew Carignan, Ryan Cook, Fautino De Los Santos and Jordan Norberto have just 98 big league appearances among them, and De Los Santos and Norberto account for 75 of those.
The key, according to Fuentes, is knowing when to offer advice and when to back off.
"Learning on your own is a big part of growing as a pitcher because I think you learn through failure," Fuentes said. "That's something that all these guys will experience -- if not this year, then at some point in their careers. I know I definitely have."
A's general manager Billy Beane said patience is required with the young relievers.
"They're young and inexperienced, but they've got good arms," Beane said. "They're going to have some growing pains, but this is the next step for them, to go ahead and get through that."
Cook, obtained from Arizona as part of the Trevor Cahill trade, has been tapped as the right-handed set-up man to complement Fuentes. That role might have gone to Devine, and it's notable that the A's are going with Cook over De Los Santos, a hard thrower who still has command issues.
Cook, 24, has yet to allow a base runner in three appearances (31/3 innings).
If the relief corps rounds into shape, it would bode well for the A's considering they also feature a rotation that might endure some growing pains of its own, with rookies Tommy Milone and Graham Godfrey.
Balfour is confident his younger bullpen mates can rise to the occasion.
"Those guys have got great arms," he said. "It's just a matter of believing in themselves and going out there and doing it."