After more than three months on the disabled list, Paxton finally returned to the mound for Seattle on Sunday.
"It's been a long, long season waiting to get back out there," Paxton said.
Paxton lasted just two batters into the fourth inning of his return as the Mariners dropped the series finale to Colorado 3-2. Making his first start since May 28 because of a strained tendon in his left middle finger, Paxton struck out four and allowed only two hits but issued three walks.
He was on a limit of 80-85 pitches making his 11th start of the year, but was pulled after throwing 66 and being unable to find command with his fastball. He'll get a few more chances to figure it out before the end of the season as Seattle would like to get Paxton three more starts.
"If I had better fastball command and was getting ahead of guys more often it would have allowed me to go deeper in the game."
Nolan Arenado, the National League leader in RBIs, capped a third inning when the Rockies scored without a base hit with a sacrifice fly for his 110th RBI of the season. Charlie Blackmon walked, advanced to second on a groundout, stole third and scored on Arenado's fly ball to deep right field.
The Rockies added two more an inning later when Willin Rosario doubled leading off, Justin Morneau walked. Both scored when Kyle Seager overthrew catcher Steven Baron trying to cut down Rosario at the plate after Dustin Garneau hit a weak groundball to third. It was the 16th error of the season for Seager.
Ketel Marte walked with one out in the eighth inning and Seager sliced a drive deep into the left field corner. Barnes raced over to make a diving catch and was able to get ball back into the infield in time for Marte to be doubled off first after advancing too far.
Seattle manager Lloyd McClendon called it one of the top plays of the year and preserved the lead as Marte likely would have scored.
"Off the bat I didn't think there was any chance he got to it," Seager said. "I thought it was going to be a double for sure and the way Marte runs you've got to think it ties the game."
Kyle Kendrick (6-12) allowed two runs over five innings to pick up his second straight victory.
Kendrick grew up about 90 minutes north of Seattle, but had never pitched against the Mariners in his career. With a small cheering section behind home plate, Kendrick won consecutive games for the first time this season.
John Axford pitched the ninth for his 23rd save in 28 opportunities.
"I came to games here as a kid, my dad use to take me to games here, so just coming here brought back those memories and pitching against a team I grew up rooting for was pretty cool," Kendrick said.
END OF INTERLEAGUE
Seattle finished 8-12 against the national league, the fourth straight year with a sub-.500 mark against the NL. That streak came after Seattle went 12 straight seasons with a winning record against the NL.
Rockies: Colorado opens a series in Los Angeles against the Dodgers with Jon Gray (0-0) still seeking his first major league victory. The Rockies are 1-6 in his previous starts.
Mariners: Taijuan Walker (10-8) makes one of his final starts of the season on Monday night against the Angels. Walker will likely have a start skipped down the stretch to control his innings.