West (1-1) allowed one baserunner -- a leadoff walk to Andres Torres in the third
-- through the first six innings. Edgar Renteria then lined a single to left on West's first pitch of the seventh.West gave up two hits, one walk and struck out six in eight innings.
The left-hander, a 6-foot-8 Houston native, missed the entire 2007 season after undergoing shoulder surgery.
Johnson (5-5), pitching on short rest, four days after he earned career victory No. 300 at Washington, allowed three runs, seven hits, three walks and struck out five in five innings.
Carroll hit a three-run homer in the second to give the Marlins a 3-0 lead. He also singled and tripled for the Marlins, who earned a split of the four-game series. Leo Nunez pitched a scoreless ninth.
After Dan Uggla a single and Ronny Paulino walked, Carroll sent Johnson's 90 mph fastball over the left-field scoreboard.
San Francisco's Aaron Rowand went 0-for-4 and had his hitting streak ended at 17 games. Renteria also singled in the ninth to have two of San Francisco's three hits.
Johnson had been 6-1 with a 2.84 ERA in nine career regular-season starts on short rest before Monday.
Notes: West's starts account for all of his major-league appearances. He'll turn 23 on June 15. ... A fan with a glove caught Carroll's homer on the fly. ... The Giants' string of five consecutive games delayed by rain ended. ... The game was played in 2:32.
