SEATTLE - Twins Assistant General Manager Rob Antony had a little gleam in his eye before Saturday's game at Safeco Field.

He had just been through another round of questions about Nick Blackburn -- and yes, the Twins are considering another demotion for the veteran righthander -- but pretty soon the conversation turned to the farm system.

The Twins have with the worst starting pitching ERA in the American League, at 5.52 entering Saturday, and their lack of front-line pitching prospects has been well-documented, but here are five pitchers who have quietly made big strides of late:

1. Jose Berrios (age 18)

The No. 32 overall pick in this year's draft out of Puerto Rico, he is 2-0 with a 0.70 ERA, 43 strikeouts and only four walks in 25 2/3 innings pitched between the Gulf Coast League and rookie-level Elizabethton.

"He's the best-looking pitching prospect that we've drafted in a long time, for me," Antony said. "He pitches and has the mound presence of a college guy. He's got good stuff, really good. He was sitting at 93-94 [miles per hour] and touching 96. He's got a good breaking ball, throws strikes, gets ahead in the count, can put people away."

2. Kyle Gibson (age 24)

After having Tommy John surgery last Sept. 7, Gibson is rehabbing for Class A Fort Myers and throwing better than he has since the Twins made him a first-round pick in 2009.

He definitely could make an impact on the Twins major league staff next year, but they will be cautious with his workload, possibly limiting him to about 100 innings. For now, there's hope that he will continue thriving on his rehab and build up his innings count in the Arizona Fall League.

3. Liam Hendriks (age 23)

He is 9-3 with a 2.20 ERA for Class AAA Rochester, which might have everyone more excited if he weren't 0-7 with a 6.61 ERA thus far in his major league career.

As good as Hendriks has been for Rochester, he still has things he can learn there. On Friday, for example, he had an otherwise strong outing ruined when he hung a breaking ball that turned into a three-run homer. Once he learns to bury those pitches and avoid those mistakes, he has the potential to be an above-average starter in the majors.

4. Pedro Hernandez (age 23)

July 28 was quite a whirlwind for the lefthander. He got traded to the Twins in the deal that sent Francisco Liriano to the White Sox on the same day his wife gave birth to their daughter.

In his first start for Rochester, Hernandez gave up six runs and 10 hits over two innings. But in his next two starts, he held opponents to three runs over 13 innings, for a 2.08 ERA.

The lefthander profiles as a No. 5 starter and perhaps even a reliever, but he is showing the control the Twins expected -- 10 strikeouts and one walk -- when they traded for him.

5. Esmerling Vasquez (age 28)

Plucked off waivers from the Diamondbacks last year, Vasquez hadn't started a game since 2008. But over his past 10 games for Rochester, including five starts, he is 5-1 with a 1.94 ERA and has held opponents to a .184 batting average. The Twins might give him a look in September.

"He's got three pitches," Antony said. "He's run out there for seven innings, and he's throwing strikes, and he's showing all the traits you look for in a starter."