The Baltimore Orioles have won four of five games and three of them have come in extra innings.
Manny Machado is responsible for the last two.
AL East-leading Baltimore (59-46) remained 2 1/2 games ahead of Toronto with another extra-inning victory Tuesday. The Orioles have won seven straight in extras and are 12-3 in such contests this season after they had 16 extra-inning wins in 2012.
"We have good chemistry in the clubhouse like we did back then and obviously we have a good bullpen as well," Machado said.
While the bullpen has a 1.50 ERA during a 6-2 stretch, Baltimore has needed heroics from Machado lately.
The third baseman delivered a walkoff homer in the 12th inning Tuesday, lifting the Orioles a 7-6 victory over Los Angeles (63-42). Machado came through with a sacrifice fly with the bases loaded in the 10th inning Sunday, securing a 3-2 win at Seattle.
He's batting .373 with four homers and 10 RBIs in 15 games since returning from a five-game suspension July 5.
Adam Jones hit his 20th homer and Nick Markakis added a three-run shot for the Orioles, who moved a season-best 13 games over .500 despite hitting .199 over the past eight games.
Jones has five home runs and 12 RBIs in his last seven contests against the Angels.
Josh Hamilton homered and had three RBIs for Los Angeles, which had a three-game win streak snapped and lost for the eighth time in 11 meetings against the Orioles.
After scoring six runs off Jered Weaver, Baltimore faces another challenge against Richards (11-3, 2.62 ERA), who is one win shy of the AL lead.
The right-hander had a seven-game win streak snapped Thursday, allowing four runs and seven hits over six innings in a 6-4 loss to Detroit. He had been 7-0 with a 1.25 ERA over his previous nine outings, striking out 70 in 64 2-3 innings.
"I feel like that's been the biggest adjustment for me this year - being in the rotation, having it set when I'm going to pitch, me having an idea of what I need to do in between starts, spending more time in the gym, little stuff like that," Richards told MLB's official website.
Richards was tagged for seven runs over 4 1-3 innings in his only start against the Orioles on July 5, 2012. He has a 9.00 ERA in five career appearances versus Baltimore.
Ryan Flaherty is 3 for 4 with a home run against him.
Kevin Gausman (4-3, 3.67) will oppose the Angels for the first time looking to build on an impressive performance. The 23-year-old rookie matched up with Felix Hernandez and scattered seven hits over 6 2-3 innings in Friday's 2-1, 10-inning victory at Seattle.
That marked the sixth time in his last eight starts that Gausman held an opponent to one run or fewer. He's 3-2 with a 4.33 ERA in five home starts this season.
Orioles first baseman Chris Davis did not play Tuesday after being sent home with a stomach virus.
''He was sick all day (Monday) and didn't seem to be making a marked improvement,'' manager Buck Showalter said.