OAKLAND, Calif. (AP) - The news just keeps going from bad to worse for Athletics manager Bob Melvin.
Not long after his club blew another lead and lost to Pittsburgh for the third straight day, Melvin learned that yet another pitcher could be headed for the disabled list.
Reliever Francisco Rodriguez left with a right shoulder strain after facing one batter in the eighth and will undergo an MRI to see how extensive the damage is.
If he does get placed on the DL, Rodriguez will join nine teammates currently there — five of them pitchers.
"We feel like we have a lot of good pieces here (but) obviously we've been going through some injuries and continue to go through some injuries, which is frustrating," Melvin said. "We played two good series and we have more injuries. It's frustrating but no more for me than anyone else."
The A's had won six of seven and took three of four from NL West-leading San Francisco before dropping three straight to the Pirates.
Adam Frazier tripled in the tying run with one out in the sixth, then scored on an infield single to spark Pittsburgh's latest win in this interleague series.
David Friese hit a two-run homer and Gregory Polanco added two RBIs as the Pirates completed the three-game sweep in their first visit to the Oakland Coliseum since 2010.
Francisco Liriano (5-8) pitched five innings to win for the first time since May 24. The lefty had lost five straight games before beating the A's to help extend Pittsburgh's winning streak to four.
"It's huge, especially to come from behind three games in a row on the road," Frazier said. "We got the split in Seattle but to get three come-from-behind wins like this, it's huge momentum heading back east to St. Louis."
Khris Davis had two hits and scored a run, while Billy Butler added an RBI double and scored for Oakland.
The A's have lost four straight after winning the opener on this five-game homestand.
They had plenty of chances to halt their skid Sunday but stranded seven runners overall, including four in scoring position in the final five innings.
"More than anything it was the situational at-bats," Melvin said. "We had some opportunities and we didn't get them in."
Pirates manager Clint Hurdle was ejected in the bottom of the sixth for arguing balls and strikes.
Oakland starter Daniel Mengden (1-4) allowed four runs in 5 1/3 innings. He struck out five and walked four.
Matt McBride was called up from Triple-A Nashville to replace injured Oakland backup catcher Josh Phegley on the roster but didn't arrive at the Coliseum until shortly before first pitch. He started and batted eighth, going 1 for 2 in two plate appearances before getting lifted for a pinch hitter in the sixth.
Pirates: OF Andrew McCutchen took the day off to rest his sore left heel. McCutchen was injured while sliding into home plate on a wild pitch Friday.
Athletics: Phegley was placed on the disabled list with what team officials are calling a right knee strain. Melvin said it's possible that Phegley will require surgery.
Pirates: Jonathon Niese (6-6) takes a four-game losing streak into Monday afternoon's start in St. Louis. The lefty has a 5.32 ERA on the road this season.
Athletics: Right-hander Kendall Graveman (3-6) pitches the series opener in Minnesota on Monday. Graveman has allowed two runs or less in six of his previous eight starts.