"It so happens that Lopez got a little banged up [Monday night], so he might have been off tonight anyway. We're just trying to pace them a little bit, but more importantly, get Willie a day at short in case we need him down the road."
Lopez fouled a ball off his left knee during his fourth-inning at-bat. He remained in the game but was removed for a pinch-runner in the ninth inning after coaxing a walk from Athletics closer Huston Street.
Betancourt has played in 85 of the Mariners' 89 games this season, two fewer than Lopez, and they continue to develop into a solid keystone combination.
"They have played good," Riggleman said. "I know Lopez has made an All-Star team  already, and there is that potential for both. They can hit, both have very good arms, good hands and both of them, in time, will learn the strike zone so they take more walks.
"With that added to their game, I think you have an All-Star combination."
Betancourt is off to a good start in July, offensively and defensively, following a June swoon, when he batted .220. He is batting .280 in July, comparable to his productive April (.300) and May (.283).
But he still swings freely, as evidenced by his five walks in 308 at-bats this season.
Lopez shares the king of swing with his sidekick, working opposing pitchers for 14 walks in 356 official at-bats.
On another subject, Riggleman said during his pregame media session that "unless there is a miraculous development, I don't think we will start [Erik] Bedard before the All-Star break."
The left-hander has been bothered by various ailments most of the season, the most recent being "tightness" in his left shoulder.
"We have the break coming up, so let's take advantage of those four days and hopefully get the nagging stuff out of the way to where he can throw all of his pitches," Riggleman said.