Though Garrett Richards has filled in nicely since ace Jered Weaver went on the disabled list, the Los Angeles Angels have sunk to the bottom of the AL with a team ERA even one of baseball's most expensive offenses can't regularly overcome.
After a wild 19-inning affair in the series opener, Richards opposes Parker as the AL West rivals continue their three-game set Tuesday night in Oakland.
Los Angeles had a 3.11 ERA through its first five games, but since Weaver suffered a broken left elbow April 7 in a loss to Texas, it has posted a 5.08 ERA and ranks last in the AL with a 4.69 overall mark.
Richards (1-1, 3.65 ERA) has gone 1-1 with a 3.98 ERA in three starts after entering the rotation. He yielded just two hits while striking out a career high-tying eight in seven innings of a 10-0 win over Detroit on April 20.
His numbers weren't great Thursday - giving up five runs and nine hits in seven innings of a 6-0 loss to Seattle - but manager Mike Scioscia liked what he saw.
''I thought Garrett pitched much better than his line scores will show,'' Scioscia said. ''As far as him getting after it and the movement on his pitches, he was terrific. It didn't work out, but I thought he pitched a strong game."
The right-hander has never started against the A's, pitching 2 2-3 innings of scoreless relief over three appearances last season, and he'll look to keep Oakland at bay while trying to avoid overtaxing his bullpen.
Los Angeles (9-16), which added Josh Hamilton in the offseason to a lineup already featuring Albert Pujols, Mark Trumbo and 2012 AL Rookie of the Year and MVP runner-up Mike Trout, has already lost five times when scoring at least five runs.
Pujols went 4 for 8 with a pair of homers after going 3 for 31 over his previous eight games, and Trumbo added a solo shot and three RBIs, but the Angels fell 10-8 when Brandon Moss hit a two-run homer in the bottom of the 19th - his second of the contest - in the longest game in the history of each franchise.
''It was a crazy game and I'm glad it's over,'' Moss said. ''That was exhausting, it really was.''
Hamilton went 0 for 8 to drop his average to .202, and he's 0 for 10 with seven strikeouts lifetime against Parker, who is battling his own struggles.
The Angels will likely have a new center fielder and leadoff hitter for this game after Peter Bourjos strained his left hamstring running out a sacrifice bunt in the 10th inning, and the Athletics had outfielders Coco Crisp and Chris Young leave with lower-body muscle strains as well.
''It stinks to play this long into the night and come out on the wrong end,'' Bourjos said.
The A's (15-12) have a 4.28 team ERA, though Parker (0-4, 8.10) appeared to be getting back on track after a solid outing in a 1-0 defeat at Tampa Bay on April 20. However, he gave up six runs and eight hits while walking three in 5 1-3 innings of Thursday's 10-2 loss to Baltimore.
He is attempting to remain positive, though he Tweeted that he was heckled by Oakland fans during his bullpen session prior to Saturday's home loss to the Orioles.
"There's certainly things he's always working on, maybe a little bit more specifically now," manager Bob Melvin told the team's official website.
The right-hander had a tough outing versus the Angels on April 9, giving up two runs and nine hits in only 3 1-3 innings of the Athletics' 9-5 victory.
Jason Donaldson, 2 for 2 with a double lifetime off Richards, is 15 for 29 with 12 RBIs over his last eight games.