The left-hander is 3-0 on the season and is coming off a strong five-inning outing against the Yankees in New York.
He is also 2-0 with a 1.64 ERA against the A's in three games in his young career -- just 20-20 against every other team. He has allowed eight hits in 22 career innings against the A's.
For more positive numbers for Boston, Daniel Mengden starts for Oakland in the second game of the three-game series -- and the righty with the Rollie Fingers moustache is 0-1 with an 8.00 ERA in two career starts against the Red Sox, both in Oakland.
Mengden, who pitched well in a no-decision against Boston in Oakland on April 22, is 0-2 with two no-decisions in his last four starts, having yielded four runs in each of his last two. He hasn't won since April 16.
The A's, who won the opener but then lost the next two games in New York over the weekend, hit three home runs and held off the Red Sox 6-5 Monday night -- improving to 15-11 over their last 26 games to get back to a game under .500 (20-21).
Sean Manaea, who threw a no-hitter at the Red Sox last month, was the winner Monday, albeit without a second no-no.
"Pretty tough place to pitch," said manager Bob Melvin. "You're not going to go out and throw a no-hitter against them, but all in all, he left with the lead (after six-plus innings) in this ballpark, that's a good job."
Closer Blake Treinen worked a perfect ninth inning for his seventh save -- and to lower his ERA to 0.93.
The loss dropped the Red Sox a half-game behind the idle Yankees atop the AL East. It also dropped the Red Sox to 11-11 after their sizzling 17-2 start.
Rick Porcello suffered his first loss of the season Monday night.
"They strung together a lot of hits, but really felt halfway decent out there," said Porcello (5-1). "Just didn't get out of the jam in the fourth, and that ended up being the difference."
According to a tweet from Chris Smith of MassLive.com, "Red Sox starters went 12-1 with a 2.17 ERA (25 earned runs, 103 2/3 innings) in the first 19 games. It marked Boston's lowest starter ERA through 19 games since 1920. Since then, Sox starters have combined for a 6-5 record with a 4.80 ERA (71 earned runs, 133 innings)."
The current Oakland roster is just 5-for-42 (.119) against Rodriguez, with only Brett Lowrie having decent numbers (2-for-6, .333). Khris Davis is 0-for-10 with five strikeouts, Mark Cunha 0-for-6 and Marcus Semien 1-for-7 (.143).
Jackie Bradley Jr. is 3-for-5 (.600) and Mitch Moreland 3-for-8 (.375) against Mengden, the current Red Sox 13-for-39 (.333) against him.
Dustin Pedroia, making his way back from knee surgery, played his first rehab game for Pawtucket Monday night and will DH for the PawSox Tuesday. He was in the Red Sox dugout after finishing his Triple-A game down the highway.