The right-hander looks to continue his solid run Thursday as he takes the mound at Wrigley Field against the Colorado Rockies in the finale of this four-game set that has featured plenty of free baseball.Arrieta was acquired on July 2, 2013, in a trade that sent Scott Feldman to Baltimore, though he came with some concerns after having elbow surgery in 2011 and a rough final season and a half with the Orioles.Cubs president of baseball operations Theo Epstein took a gamble, and Arrieta (5-2, 2.18 ERA) has turned a corner this season. He's allowed three earned runs or fewer in 14 of 15 starts and has become the most reliable starter for the Cubs (44-62) since they traded Samardzija and Hammel to Oakland on July 4.Teams reportedly have inquired and been rebuffed regarding a trade for Arrieta, who is making just $500,000 this season and is under team control until 2017.Arrieta gave up two runs in six innings of the Cubs' 6-3 loss to St. Louis on Saturday for his ninth straight quality start. He's 4-1 with a 1.77 ERA in that stretch, and manager Rick Renteria was impressed with how Arrieta responded after giving up two first-inning runs."That performance is indicative of how much he's grown," Renteria said. "If that had been a couple years ago, and he was struggling, he wouldn't be able to grind through and pitch six innings without his best command or stuff."Arrieta has never faced the Rockies (44-63), who snapped a three-game losing streak with Wednesday's 6-4, 10-inning victory. Brandon Barnes drove in the tiebreaking run one night after the Cubs' 4-3, 16-inning victory that was the longest game in both franchises' history at 6 hours, 37 minutes."We got some timely hits tonight," manager Walt Weiss said. "We got a few early, and then of course Barnesy had the big one late."Colorado has felt the brunt of Tuesday's marathon the most. Carlos Gonzalez played 12 innings in that contest and had to sit out Wednesday with soreness in his right ankle and left knee."He's not quite 100 percent with that ankle," Weiss said. "He played in that fiasco and we've got a day game (Thursday), so a lot of things lined up for him having a day off."The Rockies also had to shuffle their rotation, as Thursday's scheduled starter Tyler Matzek pitched two-thirds of an inning in relief and gave up the winning run in the 16th. Pedro Hernandez has been called up from the minors to take Matzek's place in this contest.Hernandez will be making his Colorado debut after going 6-6 with a 6.14 ERA in 16 starts and two relief outings for Triple-A Colorado Springs. He went 3-3 with a 6.83 ERA in 12 starts and two relief appearance for Minnesota last season before being released and signing a minor league deal with the Rockies.The left-hander has never faced the Cubs, who got three hits -- including a tying two-run homer in the eighth -- and three RBIs from Luis Valbuena on Wednesday. They had won five of the previous six home meetings with Colorado.Chicago acquired left-hander Felix Doubront from Boston on Wednesday and also completed the trade that sent Darwin Barney to the Los Angeles Dodgers, getting minor league pitcher Jonathan Martinez.