By Tommy Rancel //

Once upon a time, Chris Perez was regarded as the St. Louis Cardinals’ closer of the future. After a few seasons of inconsistency, a trade to Cleveland, and Kerry Wood‘s trade to the Yankees, Perez is finally closing games on a regular basis at the major league level.

Perez made his major league debut with the Cardinals in 2008 when he pitched 41 games out of the pen – compiling a 3.46 ERA with seven saves. Although he struggled with walks, he struck out more batters (42) than he had innings pitched (41.2) that year.

The right-hander would split the 2009 season between St. Louis and Cleveland after a mid-summer swap for Mark DeRosa. While his ERA jumped to 4.26, his strikeout rate improved from 9.04 strikeouts per nine innings (K/9) to 10.74 per nine. Walks were still a problem, but his BB/9 dropped slightly (4.33 in ’08, 4.27 in ’09). A flyball pitcher (his groundball rate was an extremely low 35.3% in 2009), Perez’s home run rate jumped to a shaky 1.26 per nine innings.

Perez was slated to start the 2010 season as the Tribe’s set-up man for Wood. When Wood went down with injury early in the season, Perez was temporarily given the closer’s role. Upon his return, Wood assumed control of the 9th inning. When Wood was traded to the Yankees at the July 31 deadline, Perez was once again given the title of closer.

Despite the uncertainty in roles, Perez has turned into a fairly reliable fantasy option at the back end of games. Overall, he has a 2.17 ERA over 49.2 innings. His K/9 has dropped to 8.34, no longer elite for a reliever, but still very playable. His BB/9 has dipped slightly to 3.99, a positive sign.

Speaking of progress, Perez has made his greatest strides over the past three months. Since June 1, Perez has struck out 29 batters while walking 12 in 31.2 innings. During the same time period, he has allowed just five earned runs (1.44 ERA). In the small sample size of August, he has not walked any batters while striking out nine and giving up just two runs.

Perez is certainly not the caliber of Mariano Rivera or Rafael Soriano. And his team is middle of the pack on their best day. That said, the low ERA, the stellar strikeout numbers, the unchallenged save opportunities, and the availability on most waiver wires make him an attractive option to deep AL only owners, and those looking for late-season closing options in mixed leagues.

Be warned, though: The biggest change in Perez’s results by far, though, has been a plunge
in his HR/9 rate. That’s down to a career-low 0.72 this season, and
seems to be mostly a product of tremendous luck: His HR/FB rate has
tumbled to 6.5% this season. A pitcher inducing a microscopic groundball rate of
30.3% (for comparison, Perez’s teammate Justin Masterson is generating a 62.3% GB rate) isn’t likely to avoid homers this successfully for long. Perez’s strand rate is a higher-than-average 83.6%, while his batting average on balls in play is just .254, well below the league average of about .300. His xFIP (a stat that runs along the same scale as ERA, but also adjusts for ballpark effects, aberrant home run rates, batted ball luck, and other factors) of 4.67 dwarfs his 2.17 ERA, and shows that luck has played a big role in his success.

Grab the saves, but don’t expect a Mariano-like ERA forever, especially if you’re in a keeper league.

For more on Chris Perez and other late season additions, check out Bloomberg Sports’ Fantasy Kits.