Cingrani blew through the first three innings on 36 pitches. However, Arizona's Martin Prado hit a solo home run with one out in the fourth inning for the D-backs' first hit of the game. Paul Goldschmidt then followed with a walk before Cingrani gave up a double to Aaron Hill after picking Goldschmidt off of first base.
It was then that Cingrani was joined on the mound by pitching coach Bryan Price, head trainer Paul Lessard and Baker, who took the ball from the 24-year-old left-hander, bringing the 16th start of his rookie season to an abrupt end.
"We were quite surprised," Baker said. "He was throwing the ball well, probably as well as he has all year, so for him to say something is wrong with him and for him not to continue, it had to be pretty serious.
"It shocked us all."
Entering Tuesday, Cingrani, who replaced the injured Johnny Cueto in the rotation, had gone 6-2 with a 2.60 ERA in 15 starts this season, while also contributing out of the bullpen.
Although Cingrani said he is sure he will take the mound for his next turn in the rotation, 28-year-old right-hander Greg Reynolds is a potential replacement if that's not the case. Reynolds, a former No. 2 overall pick in 2006, was called up once this season to pitch the second game of Cincinnati's doubleheader against the Giants on July 23. In five innings, Reynolds gave up five runs on eight hits and a walk.
For Triple-A Louisville this season, Reynolds has gone 12-3 with a 2.42 ERA, highlighted by a complete-game, two-hit shutout on June 21. He pitched Tuesday, which would make him available to take Cingrani's next scheduled start on Sunday against Milwaukee.
With Cueto already on the DL, though, Baker hopes Reynolds' services are not needed.
"We'll wait and see how he's doing in the morning," Baker said of Cingrani. "We certainly can't afford any more injuries on our starting staff going down the stretch here. Especially Tony, who is throwing the ball so well."
Mark Sheldon is a reporter for MLB.com. Read his blog, Mark My Word, and follow him on Twitter @m_sheldon. Jeremy Warnemuende is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.