"Making the Grade" is a four-part series analyzing the performances of various units of the 2009 Oakland A's. It kicked off Wednesday with Starting Pitching. Today: Bullpen, followed by Offense (Wednesday) and Defense (Friday).

OAKLAND -- The A's expected their bullpen to be strong in 2009, and it was.

The final makeup of it, however, was considerably different than what they'd envisioned.

Brad Ziegler, coming off a record-setting rookie season, and Joey Devine were expected to share the closer's role, and veteran free-agent signee Russ Springer factored heavily into the plan.

Instead, Ziegler ended up in more of a setup role; Devine's season ended before it started when he underwent Tommy John ligament reconstruction surgery; and Springer was largely ineffective before being waived after the All-Star break.

Yet Oakland's bullpen, which featured for the second consecutive season one of the biggest Cinderella stories in the game, finished the year as one of the American League's best. And with every key member of it under club control for 2010, it is positioned to repeat as one of the league's more enviable units.

Overall: A-
Right-hander Andrew Bailey was a struggling starter at Double-A Midland in 2008 when the RockHounds' season hit the midway point, after which Bailey, who turned 25 this May, was moved into the bullpen. The rest is history, literally. Bailey killed the Texas League in the second half that season, but he still entered Spring Training with the A's as the longest of shots to make the big league team. He didn't just make the team; he eventually took over the closer's role, was the only rookie in either league to earn a trip to the All-Star Game in St. Louis, and set Oakland's rookie record with 26 saves (and a 1.84 ERA with a remarkable 0.88 WHIP). A leading candidate for AL Rookie of the Year honors, Bailey deserves an "A+."

Righty Michael Wuertz was an under-the-radar trade acquisition, but with a devastating slider than helped him ring up 102 strikeouts in a career-high 78 2/3 innings, he established himself one of the premier setup men in the game. His 2.63 ERA looks good on paper, but Wuertz, 30, is the type of pitcher you have to see on a regular basis to appreciate how good he really is. Were it not for a 5.93 ERA over 12 appearances in July -- the likely result of having been used almost daily for the first three months -- he'd probably get twice the raise he'll get over his 2009 salary of a reported $1.1 million via arbitration this offseason. Anything less than an "A" would be insane.

Though he didn't arrive on the scene until September, lefty Brad Kilby deserves an "A," as well. He allowed one earned run in 11 appearances, with 20 punchouts over 17 innings and a 0.82 WHIP. His deceptive delivery, in which he hides the ball behind his back before unloading, is something the league is sure to examine and eventually adjust to, but his command and willingness to attack hitters suggests that Kilby, 26, will be able to counter-adjust and find a prominent role next season.

Craig Breslow was another low-profile addition, but he played a high-profile role as the bullpen's key lefty and posted a 3.36 ERA with an admirable 1.11 WHIP over 77 outings. A 29-year-old not yet eligible for arbitration, Breslow, 29, brought stability to an unstable situation -- the team's projected lefty specialists going into the season struggled -- and merits a strong "B."

Ziegler was a victim of his 2008 success in 2009. Having finished the previous year as Oakland's closer, he was touted as the co-closer with Devine when camp opened, but was ill and dinged up for much of the early season, eventually losing the job to Bailey. Ziegler is a quality big league pitcher, but he's not a closer. His sidearm delivery induces a ton of ground balls, which he got when he was on, but when he's off and leaving pitches up in the zone, he's susceptible to a string of hard-hit balls. His 3.07 ERA with a 1.50 WHIP in 69 games gets him a "B-."

Righty Jeff Gray bounced back and forth between the Minors and Majors, but he showed enough in his final callup to warrant high praise from scouts and opponents alike. Gray, 27, struggled at times, particularly in early callups, but he throws hard, has solid secondary stuff (1.29 WHIP) and has the kind of competitive fire and mound presence that should help him stave off another season on the I-80 shuttle.

The A's hoped that Jerry Blevins would make the most of his opportunity to seize the lefty-specialist role for which he was penciled in going into Spring Training, but he never quite caught on and spent much of the season at Triple-A Sacramento. His 4.84 ERA in 20 appearances with the big club leaves him with a "C-," but his 1.12 WHIP suggests that Blevins, 26, has a future with the A's -- or another club -- if he can adopt a more aggressive mindset, a la Kilby.

Righty Santiago Casilla entered the season at a crossroads. No longer a prospect, he needed to prove -- at the very least -- that he could handle the responsibility of a secondary setup role. He didn't, and for that he gets a "D." He posted a 5.96 ERA in 46 games, lost the trust of the coaching staff and now, at 29, his future with the team is uncertain at best.

Righty Edgar Gonzalez is not under club control, but as the team's designated long reliever and spot starter, he deserves the respect of a grade. But he doesn't deserve more than a "C." In 20 relief appearances, he posted a 5.21 ERA, and it's hard to imagine the A's having a burning desire to bring him back.