Yesterday, the Seattle Mariners awarded catcher Kenji Johjima a three-year, $24 million contract extension that runs through 2011. Hasty critics of the extension cite multiple reasons for the extension being ill-advised, but I disagree.

Despite being a league-average catcher offensively (98 career OPS+) who doesn’t walk (41 in 1,122 plate appearances), Johjima does have great value defensively. In 2007, he threw out 39.5% of base runners attempting to steal, only three-tenths of a percentage point behind AL leader Gerald Laird of the Texas Rangers. That was a significant improvement over 2006’s 27.9%. In addition, Johjima is durable, having caught nearly 2,300 innings between ’06 and ’07. He is, simply put, a workhorse and when you factor in both offense and defense, he is an above-average catcher.

It seems to be a unanimous opinion that Jeff Clement’s defense leaves something to be desired. U.S.S. Mariner, the great Seattle Mariners blog, claims that Clement has “bad footwork” and a “slow release.” It’s highly unlikely that Clement will even come close to matching Johjima’s defensive value in the next three years.

David Gassko of The Hardball Times did a quick statistical analysis explaining why using Clement over Johjima at catcher wouldn’t have been such a bad idea:

According to the projections we did for The Hardball Times Season Preview, the worst defensive catcher in baseball—Josh Bard—was projected to be -9.5 runs per 130 games in 2008. Let's say that Clement takes over that mantle, and is -10 runs per season. Then, for it to make sense to move him over to first base, he would have to be a +11 fielder at first. Per 150 games (a full season for a first baseman), only four first basemen project to be that good in '08: Doug Mientkiewicz, Albert Pujols, Lance Niekro, and Casey Kotchman.

So essentially, for it to make sense to move Clement over to first base, he would both have to be the worst defensive catcher in baseball and a top-five first baseman. That seems like a pretty unlikely combination.

I respectfully disagree with David mostly from a value standpoint. Johjima was worth 6.6 and 7.8 wins to the Mariners in ’06 and ’07 (using WARP-3*), respectfully. Those seasons were relatively similar with the only drastic improvement being the 11.6% jump in throwing base stealers out. So, the Mariners are getting more than 7 wins on average out of their current catcher for $8 million per season on average. Jeff Clement will make the Major League minimum, and, depending on when he’s brought up, his total salary over the length of Johjima’s contract shouldn’t exceed $2.5 million.

* David calls WARP-3 a worthless statistic, and I'm waiting for his (or others') explanation that way I can keep it or drop it from the statistics repertoire.

I compare Clement’s offense to that of Adam LaRoche (ignoring his awful start to ’08) based on a rough comparison of first basemen. LaRoche was worth 6.5 and 5.1 wins to his teams (Braves and Pirates) in ’06 and ’07, respectively, playing average defense with above-average offense.

Richie Sexson is a free agent after the season and likely won’t return to Seattle. Cot’s Contracts has a list of first basemen that will be free agents and notice that all of them are either less productive or too expensive to be worth signing at first base with Clement at catcher.

Johjima at catcher and Clement at 1B/DH for $27-28 million at most over the next three seasons ('09-'11) is presumably worth between 11-13 wins.

With Clement at catcher, the Mariners will lose between 1-2 wins with the drop-down in defense, so the Mariners will need to be able to accrue about 8 wins from their 1B/DH positions for less than Johjima’s 3-year, $24 million contract. No one on that free agent list fits that bill, so the Mariners would otherwise have to trade for an 8-win 1B/DH (not too many of those out there -- Ryan Howard, for instance, was worth 7.6 last season), which will cost them decent MLB players and/or prospects.

When it’s all said and done, it’s just not worth using Clement at catcher. The Johjima extension is actually a decent move by Mariners GM Bill Bavasi, as it saves them a lot of headaches and gives them more flexibility in the off-season knowing they won’t have to sign a free agent first baseman – they can focus their attention and money on other areas.