Thames, who has taken Ichiro Suzuki's spot in right field, is hitting .269 with three home runs and 10 RBIs in 20 games since being acquired from Toronto. He hit .400 in the Mariners' eight straight wins before going 0-for-4 in Friday's 9-8 loss to the White Sox.
Robinson, who went 3-for-4 and hit his first home run in Friday's setback, is batting .250 in 19 games, but has flashed much-improved defense with four outstanding catches in the past week. Consequently, Casper Wells has seen his playing time diminish after a rough stretch that dropped his average to .227, though manager Eric Wedge said he'll still get time against left-handed pitching.
Meanwhile, Gutierrez is batting .353 with seven RBIs in five rehab games with Triple-A Tacoma going into Friday's action.
"Hopefully, he'll be back here soon and that turns it up even more," Wedge said of the competition. "It's healthy. I think it's good. We've had a chance to watch a lot of players play and we've got a lot of guys up here that are helping us win ballgames right now and that's what you like to see."
The biggest surprise has been the outfield defense after Robinson and Thames both had some shaky moments initially.
"Trayvon was a little rocky when he got here and he's really got a lot better," Wedge said. "It took a couple days for Eric to settle in a little bit. With more playing time, I think both of those guys have settled in better. Michael Saunders has done a fantastic job all year and Wells has done a great job when he's out there."
Gutierrez was a Gold Glove center fielder in 2010, so his return would allow Saunders to move to left or right. One thing is certain, Saunders will remain in the lineup as an emerging all-around player. His four home runs in the past four games only reaffirmed his five-tool ability.
Saunders is tied for the team lead with his career-high 14 home runs and his .414 slugging percentage is obliterating his career average of .306.
"It's just part of it," Wedge said of Saunders' power potential. "You know it's going to happen because it's in there. The more he hits, the more that is going to happen. But he has to hit first. He did a nice job of handling a tough stretch there and he's reaping the benefits the way he's come out of it."