Guthrie lost 60 games over a four-year stretch with the Orioles before being traded to Colorado in February 2012 for pitchers Jason Hammel and Matt Lindstrom. Now he's back in Baltimore for the first time, poised to face his former team Thursday night as a member of the Kansas City Royals.Revenge will not factor, simply because Guthrie harbors no resentment toward the Orioles."I'll just be excited to be on the mound here again," he said. "Great ballpark with great fans. To be able to compete against friends and former teammates, it will be fun."The matchup holds plenty of intrigue, though, with Guthrie (4-0, 2.40 ERA) entering on a Royals-record unbeaten streak of 17 straight starts. He broke Paul Splittorff's 25-year-old club record with a four-hitter Saturday in a 2-0 win over the Chicago White Sox.Guthrie, who has thrown 16 2/3 consecutive scoreless innings, is 9-0 with a 2.25 ERA during the streak since losing to Texas on Aug. 3. The run began about three weeks after he was acquired from the Rockies, with whom he went 3-9 with a 6.35 ERA."He's far better than I ever imagined he was," Royals manager Ned Yost said. "He still has a great fastball at 93 mph, he can sink it, he can cut it. I just think he's comfortable in his surroundings."Guthrie loved being part of the Orioles, too, but appears to have finally reached his full potential at age 34."My time in Baltimore was a huge plus, just wonderful," he said. "I was able to learn and got a chance to start in the major leagues, something I didn't get in Cleveland. So, I have very fond memories of all the time here. I gave everything I had and enjoyed every bit of it."After flopping in Colorado, Guthrie found happiness in Kansas City. He signed a three-year, $25 million contract with the Royals in November."It was a place I wanted to go," he said. "They gave me a very fair offer, so for me it was just a perfect scenario."Much has changed for Guthrie and the Orioles since that trade -- all of it good.With Hammel becoming the staff ace, Baltimore (21-13) ended a 14-year playoff drought last season and is currently tied for the AL's best record."Jeremy did some good things for us here in Baltimore, and we were able to acquire some people that could help us through his abilities," manager Buck Showalter said. "He's having a solid year, he's coming off a great start, so I wish him well -- after he leaves here."Showalter will counter with Freddy Garcia (0-0, 2.70), coming off an impressive debut following a month in the minors after Baltimore signed him March 29. The 36-year-old right-hander gave up two runs and three hits in 6 2/3 innings of a 5-4 road win over the Los Angeles Angels on Saturday.Garcia faced Kansas City twice in relief last season while with the Yankees, giving up two runs in 4 1/3 innings. The Royals are the only team to which he's lost more than eight times, going 10-13 with a 5.69 ERA in 30 games.The Orioles are seeking a three-game sweep of Kansas City and riding a season-best four-game winning streak after a 5-3 victory Wednesday.Jim Johnson converted his 34th straight save opportunity to tie Randy Myers' club record from 1997, and J.J. Hardy homered for the third time in four games. Manny Machado added an RBI single and is hitting .404 over his last 11 games, driving in eight runs and scoring 12.Alex Gordon has homered in back-to-back games for the Royals (17-13), but they've lost three straight while getting held to seven runs.