One of the best relievers in the Carolina League is now headed to the AFL

If you were to ask an Orioles fan which lefty reliever had the best season of any of the southpaws on the O's farm this season, that fan could make a very strong case for Tyler Erwin, who had an outstanding year for Single-A Frederick. The Orioles are sending Erwin to the Arizona Fall League, which begins next month. He'll play for the Glendale Desert Dogs.

In 50 games for the Keys, Erwin, who turned 24 in August, went 4-4 with 18 saves and a 1.58 ERA. Over 68 1/3 innings, he allowed 45 hits and just one homer, with 23 walks and 84 strikeouts. He allowed a .191 average against versus lefty batters and .178 versus right-handed hitters.

Erwin led all Carolina League relievers in appearances and lowest batting average against. He ranked second in saves, fewest baserunners per nine innings (9.75) and games finished (35). He finished third in strikeouts per nine innings (11.06) by a CL relief pitcher. He converted 12 of his final 13 saves and allowed a batting average of just .058 (3-for-52) in August.

From Mesa, Ariz., Erwin will be pitching in his home state in the AFL. The Orioles drafted him in round 23 in 2016 out of New Mexico State. In three seasons on the O's farm at short-season Single-A Aberdeen, Single-A Delmarva and this year at Frederick, he has gone a combined 8-7 with a 2.22 ERA. In 137 2/3 innings, he has allowed just two homers and 43 walks, and recorded 144 strikeouts and a 1.15 WHIP.

Pitching from a three-quarters delivery, Erwin doesn't blow the ball by hitters. His fastball comes at them between 86 and 90 mph.

"He competes and throws strikes," said Brian Graham, the Orioles director of player development. "He reminds me a little bit of (Richard) Bleier. Erwin's stuff is not overwhelming or overpowering, but he gets ground balls and he gets outs and he really competes. He throws three pitches for strikes. He's a sinker, slider, changeup guy, and he really commanded the baseball. He just kept getting a lot of outs."

Added Frederick manager Ryan Minor in an interview this summer: "He's got a little funky three-quarters-type delivery. He's done an excellent job for us in every role. We used him early, then we started using him against lefties, then we started using him in the back end of games.

"He throws strikes and gets ground balls. I think he can compete at the next level. He throws a two-seamer because of his arm angle. Also throws a slider, and it's like a cutter to a righty batter that runs in on their hands. The biggest thing for him is he doesn't walk guys and goes right after hitters. He manipulates the ball a little bit and can run it in on righties. He keeps the ball in the ballpark. Tyler is a really, really, competitive kid."

Now the Orioles will get a look at him against some of the best hitting prospects in baseball in Arizona starting next month.

Because he doesn't light up the radar gun and doesn't appear on those top prospects lists, Erwin is a pitcher who will need to keep proving he can get consistent outs as he moves up. But that is probably true of even the pitchers who were first-round draft picks. Erwin doesn't get much prospect love right now, but neither did Paul Fry or Bleier.

"You know, pitchers that get hitters out, they get their opportunities," Graham said.

Erwin will be joined on the Glendale roster by lefty Chris Lee. The Orioles are also sending him to the AFL. Lee was added to the Orioles' 40-man roster after the 2015 season, but has yet to make his big league debut. In fact, this year he was taken off the 40-man in July, cleared waivers and then was outrighted to Double-A Bowie.

Lee started his 2018 season on the disabled list with a right oblique strain, and later dealt with a shoulder issue. In 2016 he had a lat injury. This has kept him out of the majors and kept him from blossoming into a top pitching prospect. He once looked headed for exactly that. But in eight games this year with Bowie, between Aug. 4 and 29, he had an 0.55 ERA, which got him back on the radar. But it increased to 3.50 when he allowed six earned runs in 1 2/3 in his last two games. The AFL might present his last chance to impress the O's brass and get back on the 40-man before December's Rule 5 draft.

Two other pitchers who have to be protected from the Rule 5 this year are headed to the AFL. They are right-handed relievers Jay Flaa and Tanner Chleborad, who both pitched at Bowie this year.

Flaa, a sixth-round pick in 2015 out of North Dakota State University, was impressive out of the Baysox 'pen. He went 3-1 with a 2.77 ERA, allowing just 35 hits in 65 innings. Lefties hit .165 off him and righties hit .143. Flaa, who throws with a nice downhill angle, has a fastball ranging between 88 and 92 mph to go with a curve and split-change.

Chleborad went 6-1 with a 3.61 ERA at Bowie. In 62 1/3 innings, he allowed 69 hits with a .285 batting average against. The 25-year-old Chleborad was taken in round 16 of the 2014 draft out of Washington State. He pitches mostly using a sinker and slider, throwing between 91 and 95 mph.

Watching Flaa and Chleborad in the AFL will help the Orioles decide if one or both of the pitchers should be added to the 40-man roster in November.

"We need to be able to evaluate our own guys. Both Chleborad and Flaa had good years and pitched well. This is a good opportunity for them to face better competition," Graham said.

The Orioles are also sending utility guy Steve Wilkerson to the AFL. And even though he is not officially on the roster yet, catcher Martin Cervenka will play for Glendale. That leaves one more player - and he will be an outfielder - for the Orioles to send to the AFL.