Lest we think that personnel decisions have been taken over completely by objective analysis, consider the case of Darren O’Day.

At the end of last season, O’Day — who turned 29 in October — had a career line of 2.89 ERA, 157 ERA+, 1.10 WHIP and 3.02 SO/BB in 180 innings. He had missed most of 2011 due to a hip injury and a loaded Texas bullpen, logging just 17 IP in the majors (with another 21 IP in the minors). But for 2009-10 combined, he ranked:

• 11th among all relievers with 3.9 Wins Above Replacement (WAR, using the Baseball-Reference version);
• 7th in Win Probability Added (WPA) among set-up men (20 saves or less);
• 6th in WHIP among relievers (100+ IP). (See table below for O’Day’s stats.)

Ten days after that birthday, he was placed on waivers by the Rangers and claimed by the Orioles.

O’Day had hip surgery during 2011, but he appeared healthy by season’s end. In three September outings, he retired 9 of 10 batters, with 4 strikeouts. And he pitched very well in the minors while rehabbing and waiting for the big club to find a need.

Although he’s a right-handed submariner, O’Day does not share his breed’s vulnerability to lefty batters. His career splits show a .244 BA/.697 OPS against lefties, with 2.94 SO/BB. The 2011 MLB average for RHP/LHB was .262/.743. O’Day has held righty hitters to .215/.597, with 3.09 SO/BB.

Despite these qualifications, and still a year away from arbitration with a salary of $1.3 million, O’Day was waived for the second time in three seasons.

The Mets had snagged him from the Angels under Rule 5 in December 2008, based on these promising numbers from 3 years in the minors, including a AAA stint: 2.76 ERA, 1.06 WHIP, 3.1 SO/BB, 36 Saves. But they cut him loose in April ’09 after four appearances, in which he allowed 2 unearned runs. It was the classic “numbers game”; the Mets felt they needed roster space so that a proven mediocrity could make a fill-in start. Here’s part of the news account from that day:

Where O’Day frustrated Mets officials, however — albeit in a tiny sample size — was dealing with inherited runners. He inherited three runners, and they all scored…. The Mets took O’Day off their roster to make room for Nelson Figueroa, who was filling in Sunday for the injured Mike Pelfrey.

O’Day pitched in 65 games for the Rangers that year, with a 1.94 ERA and 0.95 WHIP and a better-than-average strand rate, then repeated that performance in 2010. In a related story, the Mets’ top two relievers combined earned less WAR than O’Day’s 1.9, and the club finished 70-92, as their era of championship contention abruptly lurched into The Age of Lowered Expectations.

So far this year, Texas’s trash has been Baltimore’s gold: In 7 IP over 5 games, O’Day has allowed 1 run and 7 baserunners, with 7 Ks, and is 12th in WPA among AL set-up men. You couldn’t say the Rangers have missed him, with their bullpen posting a 2.43 ERA and stunning 31/3 SO/BB ratio through 13 games. The Mets, however, rank 14th in bullpen ERA and 12th in WHIP and SO/BB. Except for Jon Rauch, no Mets reliever through Friday had an ERA below 3.86. And three of their “low-budget” offseason acquisitions are getting at least twice O’Day’s salary.

Maybe he doesn’t look impressive in the bullpen. But Darren O’Day gets outs. And someday, he may even get some attention and respect.

In closing, here’s a table showing the 2009-10 stats for O’Day and for every Mets reliever: