Reliever Guido Knudson is making a push for a major league call-up

There's a good chance you have never heard of Guido Knudson before, and that's okay. A 28th round pick out of University of California, San Diego in 2011, Knudson has had a relatively nondescript minor league career. In 231 1/3 career minor league innings, Knudson has a 3.19 ERA and a 2.93 strikeout-to-walk ratio. Even this season, his numbers aren't that eye-popping. In 45 2/3 innings between Double-A Erie and Triple-A Toledo, Knudson has a 2.76 ERA and 1.25 WHIP. Granted, these would look spectacular amid the rubble that is the Detroit Tigers' bullpen, but they don't really stand out at the minor league level.

However, there's reason to believe in what Knudson brings to the table. Since arriving in Toledo in May, Knudson has held opponents to a 2.54 ERA. He only gave up one run in his first month in the International League, and has limited opponents to a .287 on-base percentage and .560 OPS in 28 1/3 innings. His 2.31 strikeout-to-walk ratio is nothing special, but that's because of a rather pedestrian walk rate.

Knudson is striking out over a batter per inning, a trend that began in 2014 when he fanned 89 batters in 77 2/3 innings across two levels. Earlier this season, James Chipman of TigsTown noted that Knudson's arsenal "has taken a step forward." He is starting to look more overpowering, allowing just 20 hits in 23 appearances for the Mud Hens. With so many relievers struggling to put together solid innings at the major league level, Knudson could soon see himself in Detroit.

Double-A Erie: Wynton Bernard, OF

Last year, Wynton Bernard was the darling of the Tigers farm system. A former San Diego Padres prospect, Bernard earned a minor league contract with the Tigers through an open-tryout. All he did after that was win the Midwest League MVP award by hitting .323/.394/.442 with 42 extra base hits and 45 stolen bases in 583 plate appearances. The Tigers placed him on their 40-man roster following the season, and challenged the 24-year-old with an aggressive promotion to Double-A.

Early in the season, it looked like Bernard was going through deja vu. He hit .315 with a .351 on-base percentage in his first 267 plate appearances, with 19 stolen bases in 26 opportunities. However, Bernard has hit a wall over the past month. Since an 0-for-4 performance on June 20, Bernard is batting .200/.281/.270. He is still creating havoc on the basepaths, with 11 steals in 13 attempts, and is actually drawing walks at a higher rate than earlier in the year. Bernard's skill set has drawn comparisons to current Tigers outfielder Rajai Davis, and may just end up being his successor if he gets things turned around down the stretch in 2015.

Single-A West Michigan: Zach Shepherd, 3B

The West Michigan Whitecaps and their fans were excited about the arrival of a 19-year-old prospect this spring. Turns out, they misidentified which teenager would be making the splash. Derek Hill has battled injuries for most of the year, but Australian infielder Zach Shepherd has held his own, batting .269/.355/.361 in 358 plate appearances. He only has three home runs, but the Midwest League is notoriously tough on hitters, and Shepherd has added 17 doubles.

These numbers aren't overly impressive -- it's only a .716 OPS, after all -- but Shepherd's age plays a big role in why scouts are so excited. He has the potential to hit for both average and power as he moves forward, and is drawing plenty of walks despite facing pitchers that are two to three years older than him. He was outside our top-20 list at the beginning of the year, but Shepherd has quickly become a top-10 prospect in the Tigers' system (TigsTown slotted him sixth in their midseason rankings). Shepherd's all-bat profile sounds similar to Nick Castellanos, but it seems like the Aussie is even more likely to end up in the outfield as he gets older.

Photo Credit: Emily Waldon / Bless You Boys

Short-season Connecticut: Ryan Castellanos, RHP

When the Tigers selected Ryan Castellanos in the 25th round of the 2015 MLB draft, it seemed like little more than using another draft pick on a family member of someone in the organization. This isn't necessarily a bad thing, every team does it. However, the younger Castellanos has already made waves in the Tigers' farm system. He has pitched at three different levels already, including two outings for the Lakeland Flying Tigers when their pitching staff was depleted following several extra-inning matchups.

It's unclear whether the Tigers will use Castellanos as a starter or reliever going forward. College pitchers are often limited in the season they are drafted in order to reduce strain on their arm. Castellanos' lone appearance in the New York-Penn League was a start, however, so it's possible we see him in the West Michigan Whitecaps rotation in 2016. As a former 25th round pick, the odds of reaching the major leagues are slim for the 21-year-old. However, with just one run allowed in his first 17 professional innings, he's off to a good start.