It's not unheard of for a reliever to be thrust into a starting role after the age of 30, though it's somewhat rare for one to succeed the way Alfredo Simon has.
Simon (12-3, 2.70 ERA) has been one of baseball's big surprises after entering the season with only 19 starts over 177 appearances for a 17-18 record and 4.11 ERA.
After Mat Latos was hurt in spring training, Simon was called on to fill in but has given the Reds (51-45) no reason to return him to the bullpen. His 12 wins going into the break tied for the most in baseball and double his previous career high set last season.
Simon, an All-Star replacement for teammate Johnny Cueto, is riding a streak of eight quality starts and has had only two outings this season where he's pitched less than six innings and allowed more than three earned runs.
The right-hander tossed a scoreless third inning in Tuesday's All-Star game despite allowing a leadoff single to Derek Jeter.
"It was big," Simon told MLB's official website. "I faced Derek Jeter in his final All-Star game. ... I just feel happy. My family has seen me pitch in the All-Star game. I'm really proud of myself."
Simon has three starts among six career appearances against the Yankees (48-47), going 0-2 with a 6.19 ERA in those outings. He's pitched at Yankee Stadium only once, allowing one run in one inning of relief for Baltimore on May 5, 2010.
With Joey Votto (thigh) back on the disabled list and Brandon Phillips out with a torn thumb ligament, Cincinnati's depleted lineup could use a nice stretch of pitching from Simon and the rotation to keep pace with first-place Milwaukee in the NL Central.
The Yankees have also been dealing with a slew of injuries, mostly to the starting rotation. CC Sabathia will have season-ending knee surgery and joins Masahiro Tanaka (elbow), Michael Pineda (shoulder) and Ivan Nova (Tommy John surgery) on the shelf.
Hiroki Kuroda is the only one left from New York's opening day rotation. Rounding out the current makeshift unit are David Phelps, rookies Chase Whitley and Shane Greene, and the newcomer McCarthy, who is set to make his second start with the Yankees.
The decimation of the staff led to the trade that brought McCarthy (0-0, 1.35) over from Arizona, where he was 3-10 with a 4.80 ERA. The right-hander made his Yankees debut July 9 at Cleveland and worked 6 2-3 innings while giving up four runs - one earned - and nine hits before New York won 5-4 in 14 innings.
McCarthy will try to keep the Yankees on track after Phelps had a solid outing in Friday's 4-3 victory in the series opener to earn his first win since June 19. Phelps gave up three runs - two earned - and six hits with seven strikeouts over 6 1-3 innings.
"Regardless of what the rotation looks like, I pride myself on being consistent," Phelps said. "When our rotation does take hits, I kind of put (it) on myself to step up."
Jacoby Ellsbury hit a two-run homer and Carlos Beltran drove in a run for New York after being activated from the concussion list before the game.
Brayan Pena, subbing for Votto at first base, homered twice for Cincinnati.
The victory opened a 10-game homestand for the Yankees, who are 19-23 in the Bronx and have 39 home games remaining - the most in the majors.