The Orioles (15-9) earned their first set of back-to-back wins at Oakland since 2005 on Thursday and Friday, and a 7-3 victory on Saturday puts them in position for their first four-game sweep at Oakland since May 22-25, 1987."We have struggled and our record has not been very good here, but winning the first three is a good way to start the (11-game) road trip," said Nick Markakis, who hit one of the team's three homers Saturday. "We've got a good lineup, and when we're going good we're as good as anybody."The A's (13-12), losers of four straight and eight of nine, are lacking that confidence."We are just pressing right now and trying to do too much," manager Bob Melvin said.Oakland is on the verge of getting swept at home in a four-game set for the first time since April 26-29, 1999, versus Cleveland.Colon (3-0, 2.42 ERA), who was on that Indians team, could help the A's get back on track as he's enjoying one of his best starts in years. The 39-year-old right-hander struck out a season-high seven and walked his first batter of the season on Tuesday, a 13-0, rain-shortened seven-inning complete game victory at Boston."That's the perfect guy to have on the mound in games like that," Melvin said, "a guy who's going to throw strikes, doesn't let the conditions affect him and keeps everybody on their toes because they know, potentially, the ball's going to be in play very quickly."He was the right man for the job."Colon has done the job in his last five starts versus Baltimore, going 2-1 with a 1.56 ERA.The A's might need a similar effort from the right-hander the way they've been struggling at the plate. Over the last nine games, they're batting .218 with four homers, none in this series.Third baseman Josh Donaldson has been one of the few bright spots. He's batting .579 (11 for 19) with eight RBIs over the last six games after matching a career high with four hits and driving in two on Saturday.The possible return of Cespedes from a strained left thumb could add some much-needed pop to an A's lineup that hit a major league-best 19 homers during its 9-2 start. He's been rehabbing at Triple-A Sacramento and could be activated on Sunday.Sunday's scheduled starter Miguel Gonzalez (2-1, 4.13) has never faced Cespedes or anyone else on the Athletics. He'll take the mound for the first time since going six innings in Tuesday's 4-3 victory over Toronto. The right-hander picked up the win after allowing just three hits and no runs until his final frame.Gonzalez will likely be throwing to Matt Wieters after Taylor Teagarden dislocated his left thumb on Saturday. Manager Buck Showalter expects Teagarden to be placed on the DL.Orioles center fielder Adam Jones, who homered on Saturday -- his first in Oakland -- will try to extend his team-best hitting streak to nine and hit safely in his 10th straight road game against the A's.Jones is 6 for 23 off Colon. Markakis is 7 for 26 with four doubles against the right-hander.