KANSAS CITY, Mo. -- A.J. Griffin, who missed 43 games with right shoulder stiffness, has not thrown more than five innings in his five starts since coming off the disabled list on June 25.

Griffin is 0-1 with a 6.17 ERA, allowing 16 earned runs in 23 1/3 innings, in those five starts. He will start Sunday for the Texas Rangers on five days' rest in the series finale against the Kansas City Royals. The two teams have split the first two games after the Rangers won 7-4 on Saturday night.

Griffin said his arm angle was not the same after the first few innings.

"It is part of it," Rangers manager Jeff Banister said.

He also acknowledged "stamina, endurance" played into it.

In his previous start on Monday at Anaheim, Griffin was staked to a 4-0 lead but gave up the lead, charged with five runs and four hits, including a home run, and three walks in five-plus innings. He has struggled in the fourth and fifth innings in his recent starts.

"That's one of the things we've talked to him about," Banister said.

Griffin threw only 76 pitches against the Angels before being removed. He threw 94 and 96 pitches in his previous two starts.

"I think every pitcher that comes back from not throwing for an extended period of time, they are going to have certain setbacks," Banister said. "One thing about A.J., we've encouraged him to continue to work on the endurance, which is going to allow him to be stronger. It's going to allow him to maintain the mechanical integrity throughout the delivery.

"The effects of not pitching, that's individual based, but for sure there is some effect. What effect, I couldn't tell you. He does get to a certain point where the mechanics do change a little bit. We're trying to get him strong enough where he can push that envelope a little bit farther down the pitch count, further along in the game."

Griffin pitched only 14 1/3 innings in the minors last season and missed the 2014 season after being shut down in spring training with Oakland with an elbow injury that would require surgery. He was 14-10 with a 3.83 ERA in 32 starts and 200 innings with the Athletics in 2013.

The Royals will counter with right-hander Edinson Volquez, who has had no success against the Rangers, which were his first club. Volquez is 0-2 with an 8.22 ERA in three previous starts against Texas. He last faced them on June 5, 2015, losing 4-0 at Kansas City.

Volquez is 2-2 with an 11.50 ERA in four starts this season against American League West clubs.

The Royals have some concern about reliever Joakim Soria, who gave up four runs -- three on an Adrian Beltre home run in the seventh inning -- in two innings. Soria has a 9.72 ERA in his past nine relief appearances.

"He really did a great job the first inning and had two outs there and, boom, they scored the run," Royals manager Ned Yost said. "And we're thinking, OK, let's hold it right there, but he just kind of got a pitch up over the middle of the plate to Beltre. He's a good hitter. I felt he wasn't dropping in velocity, so his stuff was still fine."