Marcus Stroman a top-20 SP

In 20 starts last season, Marcus Stroman recorded a 3.29 ERA and a 1.14 WHIP. Dan Hamilton/USA TODAY Sports

Earlier this year, the phrase "height doesn't measure heart" was trademarked. The owner of that trademark? Toronto Blue Jays right-hander Marcus Stroman.

That phrase, of course, is a response to those who have doubted Stroman because of his stature. He stands in at 5-foot-9, not exactly the ideal size for a starting pitcher expected to pitch 200 innings per season. To put that in perspective, Stroman was just the sixth sub-5-10 pitcher since 2001 to make a start in the major leagues. And the other five pitchers -- Fabio Castro, Daniel Garibay, Shane Komine, Arnie Munoz and Michael Tejera -- don't exactly inspire much confidence in fantasy owners.

Nevertheless, fantasy owners would be wise not to buy into the skepticism. Height doesn't measure heart, and it doesn't measure fantasy upside, either. When the dust settles, the diminutive Stroman could be a top-20 starter in 2015.

Stroman, the 22nd overall pick in the 2012 draft, made 26 appearances (20 starts) last season and finished as the No. 70 starting pitcher on the Player Rater. He posted a 3.64 ERA and 1.17 WHIP, including a 3.29 ERA and 1.15 WHIP as a starter. Those are solid numbers, to be sure. However, it's the underlying numbers that speak to the rampant optimism surrounding Stroman as we approach the start of the season.

Let's quickly run through some of the positives from 2014. Stroman posted a 53.8 percent ground ball rate, which ranked sixth best in the AL among pitchers with at least 130 innings. A high ground ball rate is good for any pitcher, but especially one who pitches his home games at the Rogers Centre, the third-most favorable park for homers last year, according to ESPN Park Factors. To wit, Stroman allowed only seven homers last season, including only two in 77 1/3 innings in the second half. That's extremely encouraging for a young hurler pitching in the AL East. The other thing about Stroman is that he rarely walks hitters. His walk rate last year sat at just 1.9 per nine innings, which ranked 12th best in the AL. That includes a 1.7 BB/9 rate in the second half.

What we're seeing here is a very strong foundation of skills, particularly for a 23-year-old. Stroman was one of only four pitchers in the American League last year to post a ground ball rate north of 50 percent and a BB/9 rate below 2.0 (Felix Hernandez, Carlos Carrasco and Hisashi Iwakuma were the others). Yet another check mark in Stroman's favor is that he allows very little hard contact. His .109 hard-hit average last season was the third-best mark in all of baseball, behind only Chris Sale and Garrett Richards.

What's perhaps most intriguing about the young right-hander, though, is the change he made midseason: He started throwing a sinker. It's not uncommon for pitchers to add new pitches either in spring training or in season, but what's interesting here is that once Stroman introduced the sinker, it quickly became the pitch he relied on most.

As seen in the table below (courtesy of brooksbaseball.net), Stroman officially added the sinker to his arsenal in July, and he used it more as the season wore on. It became his most-used pitch in August, and its usage spiked all the way to 44 percent in September.

Not only did the sinker become the pitch Stroman threw most, it also became his best pitch, based on pitch F/X data at fangraphs.com. In fact, the pitch rated as the third-best sinker in the American League last season in terms of pitch value. Stroman started using the sinker regularly during his July 19 start against the Texas Rangers, an outing in which he tossed seven shutout innings on four hits and no walks. Here are Stroman's numbers before and after adding the sinker:

Before sinker: 4.05 ERA, 1.26 WHIP, 7.9 K/9, 2.2 BB/9, 0.84 HR/9 in 13 apps. (eight starts)
After sinker: 3.38 ERA, 1.12 WHIP, 7.5 K/9, 1.7 BB/9, 0.23 HR/9 in 13 apps. (12 starts)

The new pitch helped Stroman make positive strides across the board. The lone negative is that his strikeout rate dipped slightly once he added the sinker. That said, pitching more to contact allows him to go deeper into games, and there's still reason to believe he has higher strikeout potential than we saw in 2014.

Stroman averaged 93.5 mph on his fastball last year (seventh best in the AL), and he whiffed 10.6 batters per nine innings during his minor league career, which includes an 11.4 K/9 rate in seven starts at Triple-A. Many young pitchers don't see their strikeout numbers translate to the majors right away, so he could still push his strikeout rate closer to a batter per inning. After all, he threw three different pitches last year (curve, slider and changeup) that generated 13 percent or higher swinging-strike rates. Among the 13 pitchers who whiffed 200 or more batters last year, only two (Corey Kluber and Felix Hernandez) had three swing-and-miss offerings at 13 percent or higher. Stroman clearly has the stuff to miss bats.

And it's not just that we're excited that Stroman added an effective sinker. That's really just the cherry on top. As noted above, Stroman's sinker graded out as the third best in the AL last year in terms of pitch value, but his other pitches graded out extremely well, too. According to fangraphs.com, four of his six pitches graded out positively in 2014. Those four each ranked in the top 25 in the AL, and three of the four were in the top 13. In short, Stroman's repertoire is downright nasty.

There's one more significant change for Stroman heading into 2015 that's worth discussing, and that's the upgrade the Jays made behind the plate. Russell Martin signed a five-year, $82 million contract with Toronto during the offseason and will replace Dioner Navarro as the team's starting backstop. Martin undoubtedly gives the team a big offensive boost, but he's just as valuable from a defensive standpoint. Pitch framing by catchers has become a hot topic during the past couple of years now that framing data has become more readily available. And let's just say that the difference between having Martin behind the plate instead of Navarro shouldn't be undersold.

According to framing data on statcorner.com, Martin ranked top 10 in baseball in runs saved last season with 11.7. Navarro, meanwhile, ranked third worst at minus-20.0. Martin also generated 110.9 more called strikes last year than predicted, according to Baseball Prospectus. Dioner Navarro generated 69.5 fewer than predicted. Yep, Martin will definitely have a positive impact on Stroman's numbers in 2015.

Finally, like it or not, a good portion of a starting pitcher's fantasy value is tied to wins. Chasing wins can often be an unfruitful pursuit, but the Jays should provide Stroman with plenty of run support in 2015. Toronto finished top five in baseball in 2014 in runs scored, and its offense got only better during the offseason with the additions of Martin and Josh Donaldson, both of whom sported top-five wOBAs at their respective positions last year. If Stroman pitches to his potential, wins shouldn't be hard to come by.

To recap, we've got a 23-year-old who induces tons of grounders, rarely hands out free passes and allows very little hard contact. He possesses a filthy assortment of pitches, including three offerings that generate lots of swings and misses, and has a long track record of racking up whiffs in the minors. He's now got one of the game's top pitch-framers catching him, and the offense behind him should be improved. Best of all, he'll get to incorporate his best pitch -- the sinker -- for the entire 2015 season. In other words, what he did in 2014 was plenty impressive, but it could be just the tip of the iceberg.

The latest average draft position (ADP) data at Mock Draft Central has Stroman being drafted 66th among starting pitchers and even going undrafted in some drafts. The Toronto righty is building some buzz this preseason, so his ADP could rise a bit during the next month. Either way, there will be tons of profit potential built into his draft-day price tag. This means you won't have to draft Stroman as anything close to a top-20 starting pitcher. You can, however, draft him knowing he could very well finish the season as one.