LOS ANGELES -- Matt Harvey's addition may be the biggest news regarding the Reds' rotation, but it's the young arms already in place that are giving the club reasons for optimism.
The trio of Luis Castillo, Sal Romano and Tyler Mahle has shined during the Reds' season-high three-game winning streak, allowing just three earned runs through 16 2/3 innings for a combined 1.62 ERA in that span.
"We've got to have [good starting pitching], there's no doubt about that," catcher Tucker Barnhart said. "To see the young guys continue to get better and grow and learn as Major Leaguers, it's encouraging, for sure."
Castillo held the Mets to two runs and three hits while striking out seven in Tuesday's win, and Romano wrapped the series at Great American Ball Park by pitching six innings of one-run ball with seven K's on Wednesday. Mahle allowed just an unearned run in five innings of work in Thursday's opener at Dodger Stadium.

All three hurlers are 25 or younger and made their Major League debuts with the Reds in 2017.
"These are the guys the organization has been waiting on for a few years," interim manager Jim Riggleman said. "There's others in the mix that have had shots at it and have gone back [to the Minors], but they'll be back here. Guys like [Jackson] Stephens, [Brandon] Finnegan and [Cody] Reed.
"Sometimes you don't succeed that first time through and you go back down, you come back and you're better the next time. But these three guys have held onto their spots pretty well since they came up here last year."
Worth noting
• Right-handers Michael Lorenzen (right shoulder strain) and Anthony DeSclafani (left oblique strain) will begin rehab assignments Monday with Double-A Pensacola. DeSclafani is scheduled to start for the Blue Wahoos and go four innings or 60-65 pitches, while Lorenzen will pitch in relief (one inning, 20 pitches).
Both pitchers saw action in an extended spring game in Goodyear, Ariz., this week. Lorenzen pitched an inning (15 pitches) on Thursday, and DeSclafani threw three innings (39 pitches) as well as a nine-pitch bullpen Wednesday.
• The Reds slashed just .220/.299/.309 and scored 61 runs (2.9 per game) en route to a 3-18 record over their first 21 games this season. But with Scott Schebler and Eugenio Suarez back at full strength after early season injuries and Joey Votto heating up at the plate, the club is hitting .264/.345/.446 with 22 homers and 91 runs scored (5.4 per game) in the 17 games since.
"I just think the first couple of weeks, not coming out of the gate real hot and then losing Schebler and Suarez, that's a recipe for disaster and that's what happened," Riggleman said. "And now they're all back and they're playing pretty good."