The Houston Astros (30-19) lead the AL West by five games and hope to continue their success through the months of June and July. If that happens to be the case, they're going to need to make a trade for a starting pitcher to add more depth and reliability.

Dallas Keuchel has been the lone consistent starter on the Astros' staff. He's 6-1 with a 1.98 ERA, 0.96 WHIP and 49 strikeouts in 10 starts (72 2/3 innings) while starters Lance McCullers, Collin McHugh, Roberto Hernandez, Scott Feldman, Brad Peacock and Brett Oberholtzer combine for a 12-10 record with a 4.43 ERA in 34 starts.

The club's starter's ERA (4.25) ranks 19th in the MLB.

With injuries to Peacock and Oberholtzer and the inconsistent pitching from McHugh, Hernandez and Feldman (now out for six weeks), general manager Jeff Luhnow is likely to explore the trade market as the deadline approaches if the team keeps winning. Recent rumors find a few names have already been discussed.

"Aaron Harang, who could emerge as a trade target for many teams, has at least been discussed by the Astros, who will need to lengthen their rotation ... While Cole Hamels is probably out of their reach financially ($24M per), Johnny Cueto is at least on their radar," writes Jon Heyman of CBS Sports.

It's unknown if Hamels is completely out of the discussion, but it'll definitely be a costly acquisition for Houston in terms of prospects and money. ESPN Insider Jim Bowden previously suggested the club go after the Philadelphia Phillies' ace.

"A trade for a top-of-the-rotation-type starter or the rapid development of pitching prospect Mark Appel would be a difference-maker for the team," he wrote earlier this month. "The latter is unrealistic; it's unlikely Appel is able to develop that quickly. The timetable for him to reach his potential is probably sometime in 2016. Therefore, I think it would make more sense for the Astros to package Appel and trade him to the Phillies for Cole Hamels."

Appel was the club's first-round draft pick in 2013 and he's currently struggling at Double-A Corpus Christi with a 5.85 ERA and 1.775 WHIP in his first nine starts this season. It's unknown if the Phillies want another pitching prospect because their Double-A affiliate is stacked with young pitching talent.

Harang and Cueto seem more realistic because they'll both hit free agency after this season and cost much less in a trade than Hamels. Both veterans would bring a different aspect to the Astros' rotation - Cueto would act as another ace alongside Keuchel while Harang would provide reliable depth at the No. 3 or No. 4 spot.

The fact that Luhnow is considering such options this early indicates he and the front office are trying to figure out what would be the best move for the rotation in the event they're still competing in late July and need to add another piece.

Houston reportedly signed Cuban right-hander Yoanis Quiala a couple of days ago, according to Evan Drellich of the Houston Chronicle. Quiala was a reliever in Cuba, but it's said the Astros will work on making him a starter. He could eventually become an option down the road as well, but an established veteran is probably a top priority.

Luhnow previously mentioned the team would be active on the trade market if they have a good chance of being relevant for the rest of the season. That looks to be the case right now, which will continually spur rumors.