When the Blue Jays signed Russell Martin it could be argued that it was the biggest investment in catcher defense of all time.

While Martin is coming off a strong year with the bat the reality is that he projects as only a slightly above-average hitter going forward. His career wRC+ is 106 and Steamer is predicting a 111 wRC+ for next year. Last year's effort was largely driven by an inflated .336 BABIP which was well above his career .279 mark.

Brian McCann signed a similar deal last offseason, but he did so coming off six straight 20 home run seasons where his wRC+ only dipped below 119 once. He was thought of as an impact bat, as well as a good defensive catcher. On a similar deal Martin is being paid to be a good bat and an impact defensive catcher.

This is the biggest free-agent contract for a catcher that values defensive ability as highly as offensive output. Martin doesn't get $82 million if he isn't considered to be a game-changer behind the dish.

The first major component of Martin's game-changing defensive skill is his arm.

Martin that has gunned down 73 base runners in the last two years, holding runners to a stolen base percentage of only 60.6%. At that rate when teams try and run on the Canadian catcher they are costing themselves runs in bunches. At times, Martin makes nabbing potential base stealers look downright easy:

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In this clip he is referred to multiple times as a "sniper" which seems simultaneously very accurate and completely out of place:

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Pay close attention to how nonchalant Martin is after catching Denard Span here:

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Just another day at the office:

An arm that both deters and punishes theft and an above-average bat is a great combination. However, they're not enough to justify the biggest free-agent contract in franchise history. At the end of the day the Blue Jays do not make this deal with Martin unless they believe in the value of pitch framing.

In Scott's article about the signing earlier this week he did a good job of summarizing Martin's total value according to different framing metrics, so I won't go too far down that road again. I do think that it's fairly incredible that StatCorner's data indicates that Martin was 233 calls or 31.7 runs better than Dioner Navarro last season. While it's unfair to take those numbers purely at face value, or imagine the Jays just bought themselves three wins per season on framing alone, the upgrade is substantial.

It's apparent that Martin is a good framer and Navarro is not, but there's more to the story. Martin gets you strikes that Navarro doesn't, but which ones? Thanks to Baseball Savant it's possible to answer that question. To compare the two catchers' framing abilities I looked at which pitches outside the strike zone they were able to get called as strikes.

The following pictures tell the tale. The boxes that are meant to indicate the strike zone in these heatmaps are slightly off, so focus on the colored areas. The following heatmap shows the pitches outside the zone that Dioner Navarro got called as strikes:

Navarro has done an alright job on the the inside and outside corners and gets a spattering of calls down low. Compare that to the the strikes Martin is getting outside the zone and the difference is clear:

Russell Martin is going to get you the low strike that Navarro isn't. The next question that comes up is which Blue Jays pitchers need that low strike the most?

Using Pitch/Fx data, I calculated which pitchers currently on the roster threw pitches in the lower third of the strike zone or below most frequently last year. Some of the sample sizes here are on the smaller side because I included every pitcher who with at least 20 innings pitched.

There are a couple of things worth noting here. The first is that while Estrada pops up here as the first guy, he threw to known pitch-framing ace Jonathan Lucroy last season so Martin wouldn't actually represent an upgrade. Additionally, there is no way that all of these pitchers appear for the Jays next season (Happ and Estrada may wind up being mutually exclusive) and we don't know whether Dickey will throw to Martin yet or not.

The pitcher I'm most interested to see paired with the 31-year-old backstop is Stroman.The team's de facto ace had an absolutely extraordinary debut in 2014 and could improve next season, especially given that his pitching style appears to gel with Martin's strengths.

Another thing to watch going forward is whether any new pitchers the Jays bring in during the offseason have low-ball tendencies that take advantage of Martin's framing strengths.

Even if we leave aside the more or less unprovable idea that Martin can add significant value to this team with his leadership and game calling, it's clear that signing him will have a pretty significant effect on the success of this team's pitchers. Based on his pitch-framing numbers, it appears the upgrade over Navarro will be astronomical.

Given what the Jays are paying for Martin, it kind of needs to be.