Oswaldo Mieres played state-side in 2013 for the first time in his career. The 21-year old right-hander spent time in the bullpens of Arizona and Billings.
Mieres started his season on June 22nd against the Brewers and he pitched 1.2 scoreless innings. He allowed just a hit and walk and struck out 4 batters. He followed that up with another scoreless inning of work against the Dodgers on the 25th. This time, he gave up a hit and produced 2 strikeouts. Then, he got hit around a little in his final game of June while visiting the Mariners. On the 27th, he gave up 2 earned runs on 3 hits and a walk in 2 innings plus struck out 4. In just 3 games during June, Mieres threw 4.2 innings and accumulated a 3.86 ERA and 1.50 WHIP. He also racked up 10 strikeouts to just 2 walks.
July would start with a poor outing at the Rangers. On the 1st, he gave up 2 runs, 1 earned, off of 3 hits and struck out 2 batters in 1.2 innings. Then, he threw 2 hit less innings against the Indians and struck out 2 more batters on the 6th. Visiting the Royals on the 10th, Mieres would leave the game after 2 innings, 2 unearned, 2 hits, a walk, and 4 strikeouts were added to his totals. Next, he made 4 appearances without giving up a run. On the 13th, he did so against the Padres in 1.1 innings with just a hit and 2 strikeouts. The 17th saw him throw a perfect 9th inning against the Brewers and another strikeout. On the road again, he saw 2 innings of action against the Mariners and gave up a hit and walk and struck out 3. Against the Indians on the 26th, the bad guys scored 2 earned runs off of 2 hits but struck out 5 times in 2 innings. He finished the month on the 29th and threw 1.1 perfect innings against the Brewers. Tallying up a really good month, Mieres went 13.1 innings in 8 games and built a 2.03 ERA and 0.83 WHIP. He also assembled an impressive ratio of 19 strikeouts to just 2 walks.
Mieres would throw 3 more scoreless outings with Arizona in August. He did so against the Dodgers on the 1st in an inning with 2 walks and 3 strikeouts. He went another inning against the Giants on the 7th and gained another strikeout. In his final game with Arizona, he threw an inning at the Giants park and gave up a hit. On the 12th, he moved up to Billings and surrendered a hit in one inning of work against Helena and added a strikeout. At Idaho Falls, on the 16th, he would give up an earned run in 1.1 innings from 2 hits and a strikeout. Then, he held Ogden scoreless in 1.2 innings on the 19th. He allowed just a hit and struck out 2. Once again, he faced Ogden on the 24th, but in Billings. In that game, he went 1.1 innings and gave up 2 earned runs due to a hit, 2 walks, and one strikeout. The 29th would bring August to an end for Mieres with a perfect inning in Great Falls and a strikeout. In August, Mieres tossed 9.1 innings over 8 games where he amassed a 2.89 ERA and a 1.07 WHIP. His strikeout to walk ratio fell to 10 to 4.
In September, Mieres would find his way into two games. He held the Brewers scoreless in both games. In Helena, on the 1st, he went 1.1 innings and allowed a walk and struck out one. Then, at home on the 4th, he was perfect in 0.2 innings and added another strikeout.
Season Stats
| Team | W | L | SV | ERA | IP | H | HR | BB | K | WHIP | K/BB |
| AZL Reds | 1 | 2 | 3 | 2.14 | 21.0 | 15 | 2 | 6 | 33 | 1.00 | 5.5 |
| Billings | 1 | 0 | 2 | 3.24 | 8.1 | 5 | 1 | 3 | 8 | 0.96 | 2.7 |
Overall Thoughts
After missing the 2012 season Oswaldo Mieres returned wit a vengeance and dominated over his 21 appearances between the Reds and Mustangs. The right hander posted a 2.45 ERA in 29.1 innings where he allowed 9 walks and had 41 strikeouts. After a real strong season he could push for a spot in Dayton to begin the 2014 season.