Joaquin Benoit is a good get for the Mariners, but temper your expectations

Eternal set-up man Joaquin Benoit was traded yesterday from the potentially rebuilding Padres to the Mariners, who could perhaps be more aptly characterized as retooling. Two minor-leaguers, Enyel De Los Santos and Nelson Ward, are heading to San Diego as compensation.

De Los Santos, a nineteen year-old right-hander, was signed for just $15,000 in July of 2014 but moved to the U.S. quickly. He is projectable with high strikeout numbers and a fastball that touches 97. Having pitched in the lower minors for only one year, he is still something of a lottery ticket. Ward is a 23-year-old infielder who is yet to make it out of Single-A and looks to be nothing more than a depth piece. He does, however, bat left-handed, providing a bit of extra value.

The trade looks pretty simple from the Padres' perspective; a 39-year-old reliever is of little use to a team that does not appear to be in contention next year. By trading Benoit, San Diego saves the $7.75 million he is owed in 2016 while acquiring a piece that might be useful during their window of contention. If De Los Santos develops into a mid-rotation starter down the road, then San Diego looks like geniuses. If nothing comes of the two minor leaguers, then at least the Padres save around 8 million at no real present cost.

From the Mariners' side, there is a clear fit were Benoit is concerned. Seattle relievers posted the sixth-worst ERA among MLB teams in 2015. Their collective xFIP was 4.17, suggesting that the problem was more ability than luck.

Whether he sets up or closes, Benoit should be a welcome addition. The former Ranger has not posted an ERA above 2.40 since 2012 and has shown a consistent ability to sustain a low batting average on balls in play. Over the past three seasons, only Koji Uehara and Tyler Clippard have BABIPs lower than Benoit's .230 (among pitchers with at least 150 innings over the same period).

There is, however, some concern surrounding Benoit. His strikeouts per nine innings, typically above or close to 10.0, fell to 8.68 in 2015, his lowest since 2008. In addition, his walks per nine innings grew to 3.17, his highest since 2008. And, perhaps most concerning, Benoit's home runs allowed per nine innings ballooned to 0.96, his highest since 2012. Benoit struggled with the long ball in his early years when he was (predictably) less effective but appeared to have the issue under control in 2013 and 2014.

When looking for the root of the problem, velocity is always the first suspect, especially for a 39-year-old reliever. Benoit's velocity has held steady, averaging just over 95 miles per hour on his fastball for the third straight year. That's not it.

Benoit's second-favorite pitch is his splitter, so we'll look there next. The reliever relied on the pitch more than ever in 2015, throwing it a career high 34.9 percent of the time. The following chart from Brooks Baseball shows the vertical movement on the pitch since 2007:

The splitter has lost a large portion of its vertical movement since 2010. However, the results show that this may actually be a good thing: Benoit's slugging percentage allowed when throwing a splitter was .181 last season, the second lowest of his career. His lowest was in 2014, when he allowed a .065. It appears that less vertical break is a good thing for Benoit.

Benoit throws either his fastball or splitter 80.4 percent of the time. So if his two primary pitches have been so successful, why might he have struggled? One answer could be luck. Benoit's home run per fly ball rate rose to 11.9 percent last season, his highest since his miserable 2012 season and second highest since he became a reliever. This is especially problematic for a pitcher like Benoit who struggles to induce ground balls: throughout his career, 63.8 percent of batted balls against him have been hit in the air.

That being said, luck may not be the thing. The following chart, with data from Baseball Heat Maps, shows the average distance, in feet traveled, of all the fly balls, including home runs, that Benoit allowed in various stages of his career:

The average distance traveled in fly balls increased by about 3 and a half feet relative to his career average, but by just over 6 feet compared to 2014. This is somewhat problematic, as it appears that the increase in home runs may have been somewhat performance-based rather than simply luck.

It's worth nothing that Benoit is being traded to a team that plays half its games at Safeco Field, which is notorious for depressing home run numbers. The stadium has posted an average park factor for home runs of 0.948 over the past three years, with 1.0 being average and numbers below 1 beneficial to pitchers. However, Petco Park in San Diego is considered a pitchers park as well, with an average park factor of 0.943 over the past three years, so the change in venue will probably be overstated.

Joaquin Benoit probably would have been the Mariners' best relief pitcher last season and projects to be just that in 2016. However, expectations should be tempered since Benoit saw a quiet decrease in his peripheral numbers last season and appears to have regressed in his ability to prevent the long ball. Given the risky nature of prospects and the fact that many of the Mariners' core players (Felix Hernandez, Nelson Cruz, Robinson Cano) are beginning to age or are simply old, it still makes sense to take the present upgrade in Benoit, even if he projects as more of a good reliever than a great one going forward.

Tom O'Donnell is a contributor at Beyond the Box Score. He is also a junior at Colby College in Waterville, Maine. You can follow him on Twitter @Od_tommy.