The right-hander could find the going a little tougher against a San Francisco Giants team that has busted out of its slump.
McAllister will try to help the Indians even up this three-game set with his career-best fourth straight win Saturday, while Tim Lincecum seeks his second straight victory for the Giants.
The surprising McAllister (3-0, 2.28 ERA), who was drafted by the New York Yankees eight years ago, posted career highs with nine wins and a 3.75 ERA in 2013. More importantly, he seemed to make tremendous strides when he allowed two runs over 16 innings in his last three outings.
McAllister has picked up where he left off last season, giving up six earned runs over 23 2-3 frames in his first four starts - all victories for Cleveland (11-12). He also has not allowed a home run in 31 consecutive innings dating to last season.
On Monday, he surrendered two earned runs over six-plus innings to beat Kansas City 4-3 for his third straight win.
"He didn't let anything rattle him," manager Terry Francona said. "He worked to execute pitches. He was strong."
Although he's never faced the Giants (13-10), McAllister has pitched well with a 2-1 record and 2.49 ERA in four career interleague starts. In his only outing versus the NL this season, he shut out visiting San Diego over 7 2-3 innings in a 2-0 win April 9.
Since totaling 10 runs and 32 hits with four home runs while dropping five of six, San Francisco has put up 17 runs and 21 hits, including seven homers, to win its last two.
Michael Morse hit his sixth home run and third in two games Friday, while Angel Pagan and Hunter Pence added two hits apiece in a 5-1 win. Pence has been on a roll, going 9 for 16 over his last four games.
Since giving up 11 runs and four homers over 10 innings in his first two starts, Lincecum (1-1, 6.43) has allowed four runs and two homers in 11 innings during his last two. He recorded his first quality start Sunday, surrendering three runs and striking out seven in six innings of a 4-3 win at San Diego.
"I felt he did a great job of keeping the ball down all day and elevating it at the right times," Posey told the team's official website.
That command has been lacking in Lincecum's recent interleague home starts. He's walked 16 and allowed 33 hits over 26 innings while going 1-4 with a 6.92 ERA in his last five versus AL clubs at AT&T Park.
After averaging 4.4 runs while totaling 43 hits during a 4-1 stretch, the Indians scored their only run Friday on Nick Swisher's RBI single in the third inning. The bottom six spots in Cleveland's lineup were a combined 0 for 21.
Swisher and Jason Kipnis had four of the team's five hits. Swisher is 7 for 20 over his last five games, while Kipnis has gone 5 for 12 in his last three.
Posey was hitless in three at-bats in the opener and is 3 for 36 (.083) over his last 12 games.