Preview: Orioles at Athletics

The Oakland Athletics try to extend their season-high home winning streak to eight games when they meet the Baltimore Orioles on Saturday in the middle contest of a three-game series. It appeared Oakland's run would come to an end Friday when nemesis Manny Machado hit a two-run homer in the seventh inning to give Baltimore the lead, but Josh Donaldson's three-run homer in the ninth gave the Athletics a 5-4 victory and their 12th victory in 13 games at O.co Coliseum. Machado was playing his first game against Oakland since a bat-throwing incident involving Donaldson on June 8 brought a five-game suspension and the ire of the Athletics.

"I enjoy those moments," Donaldson told reporters after belting his 21st home run and helping Oakland maintain their lead of 1 1/2 games over the Los Angeles Angels in the American League West. The Orioles lead the AL East by four games over Toronto and the New York Yankees. Baltimore's Wei-Yin Chen has never lost to Oakland in four outings (3-0) and opposes former Oriole Jason Hammel, who makes his second start since being acquired from the Chicago Cubs.

TV: 9:05 p.m. ET, MLB Network, MASN2 (Baltimore), CSN California (Oakland)

PITCHING MATCHUP: Orioles LH Wei-Yin Chen (9-3, 4.15 ERA) vs. Athletics RH Jason Hammel (0-1, 3.60)

Chen won his second straight start after allowing three runs and eight hits while striking out six in 5 2/3 innings of Baltimore's 4-3 victory over Washington on July 10. The Taiwan native, who turns 29 on Monday, has lost once in his last 12 turns (6-1) and is 4-1 with a 4.58 ERA in seven road outings this season. Chen, who received a no-decision after permitting two runs in 6 1/3 innings of the Orioles' 4-3 loss to Oakland on June 6, has yielded eight home runs in his last five starts.

Hammel, who was 15-14 with a 4.27 ERA in two seasons with Baltimore, allowed three runs (two earned) in five innings of a 5-2 loss at San Francisco on July 9 in his Oakland debut. "(It) was a grind and they grinded me pretty good,'' the 31-year-old South Carolina native told reporters. Hammel, who is 4-0 with a 1.80 ERA in five appearances (two starts) in Oakland, is 0-4 with a 6.68 ERA in eight games (six starts) against Baltimore, but hasn't faced his former team since 2008.

WALK-OFFS

1. Oakland, which is 40-16 in its last 56 home games against the Orioles, has not used a rookie in 2014, the longest stretch to start a season without one since Baltimore in 1971, according to Elias Sports Bureau.

2. In 34 games since June 9, Baltimore's rotation has posted a 3.17 ERA, lowering the starters' ERA from 4.61 to 4.07 for the season.

3. The Athletics are 9-3 in their last 12 games decided by two runs or fewer after starting the season 12-17 in such contests.

PREDICTION: Athletics 3, Orioles 2