De La Rosa tries to win a fifth consecutive start Tuesday when the visiting Rockies square off against the AL-worst Houston Astros.De La Rosa (6-3, 3.40 ERA) has given Colorado a huge boost in his first full season since undergoing Tommy John surgery, and he's been especially good this month. The veteran left-hander has compiled a 2.31 ERA in winning each of his last four outings -- his best such stretch since winning a career-high seven straight in 2009."With the amount of time he missed, a year and a half, I don't think he was going to come into spring training and be lights-out," manager Walt Weiss told MLB's official website. "It's been a process with Jorge. He's gotten better and better. To be honest with you, where he's at right now after missing that much time is real impressive."De La Rosa turned in another great display Wednesday in a 4-1 victory over Arizona, allowing one run and six hits over 5 1/3 innings. He threw a season-high 103 pitches."I think I can get a little more strength in my arm, but I can't complain," he said. "My velocity's very good. All my breaking stuff is working very good. And I'm glad to feel the way I feel right now."While De La Rosa has gone 4-0 with a 2.42 ERA at home, he's 2/3 with a 4.05 mark on the road.The Astros (15-36) counter with Jordan Lyles (2-1, 5.40), who's coming off his own splendid performance. The right-hander gave up one run and six hits over six innings Wednesday, earning the win during a 3-1 victory over Kansas City."That's the best I've seen him throw in a long time," catcher Jason Castro said. "He had command, didn't miss. When we were trying to go certain locations, he missed where we were trying to go. He didn't leave really anything over the plate for guys to hit and that's big when you can do that."Lyles is 0-1 with an 8.53 ERA over three appearances -- one start -- against the Rockies (27-24), who find themselves on the verge of a season worst-tying fourth consecutive loss.Colorado collected 13 hits but went 3 for 18 with runners in scoring position during Monday's 3-2, 12-inning defeat. The Rockies have gone 8 for 44 in such situations during their skid."It's difficult to win that way, when you leave over 10 runners on base and not being able to get the big hit," Carlos Gonzalez said. "It's frustrating."After suffering a three-game sweep at the hands of Oakland, Houston bounced back to post its ninth home win in 29 tries. Carlos Pena had two RBIs and Brandon Barnes came through with a game-winning ground-rule double with two outs in the 12th for the Astros' first walkoff win."I think these kind of wins are definitely something that can catapult you forward from just an energy standpoint," manager Bo Porter said. "Finding a way as a team and to come out on top, that momentum can carry over."The Astros will need to be careful with Gonzalez, who's batting .411 with six homers and 16 RBIs during a 12-game hitting streak in the series.These clubs play two more games in Colorado following this contest.