Franklin Gutierrez has played all of 18 games with the Mariners this season and none within the past two months. But tonight he’s back in the starting lineup and batting third as the Mariners open a series against the Texas Rangers. To clear a roster spot the Mariners designated Aaron Harang for assignment. What does this mean as far as who will take Harang’s place in the rotation? One possibility is Class AAA starter Taijuan Walker. The Mariners now have 10 days to trade or release Harang who went 5-11 with a 5.76 ERA over 120 1/3 innings in Seattle’s rotation. As for Walker Mariners GM Jack Zduriencik hinted last week he was considering adding him to the team’s list of September callups. The most heralded of the so-called “Big 3” prospects the team has been touting in the minors going on two years showcasing Walker would allow the Mariners to add to the list of young players they’ve been showcasing in the majors this season.