The Rangers, after winning 13 of their last 16 games, finished with a record of 67-95. It is the fifth-most losses in club history and most since a 99-loss season in 1985. Their 33-48 record at home was the worst in club history.
They were 14-8 under interim manager Tim Bogar, who now prepares for a formal interview and waits to see if he will continue in the job in 2015.
"It was a good run," Bogar said. "We played some good teams down the stretch and we were really competitive. That's all we can ask ... pretty solid. If you ask Oakland, they'll tell you they beat a pretty good team today."
Bogar began the day undecided whether to pitch right-hander Nick Martinez or left-hander Derek Holland, who had been scratched from Saturday's game because of a migraine headache. He ended up using both, but Martinez got the start, taking the loss to finish 5-12 with a 4.55 ERA.
Martinez went 5 2/3 innings and allowed two runs on four hits. He did not walk a batter and struck out two. All four hits came when the Athletics scored two runs in the second inning. Brandon Moss led off with a double and scored on a triple by Josh Reddick. After Jed Lowrie popped out, Stephen Vogt singled to center to give the Athletics a 2-0 lead.
"I felt great," Martinez said. "I definitely felt the adrenaline and the crowd ... the whole atmosphere of the game. I felt prepared. I left a pitch up in the sweet spot for Moss, followed by the triple. After that I made some good pitches."
The Rangers had one big threat in the fifth inning when Tomas Telis doubled and Ryan Rua reached on an infield single. With runners at the corners and none out, Gray struck out Luis Sardinas and then got Adam Rosales to ground into an inning-ending double play.
Holland, who had to take some serious medication over a 24-hour period, followed Martinez to the mound and threw 2 1/3 scoreless innings before giving up two runs in the ninth.
"I tried to do everything I could to get out there," Holland said. "I tried to do as much as I could, things just didn't go our way."
Gray allowed six hits and struck out five. He did not walk a batter as the Rangers did not draw one in their final four games.
The Rangers ended the season with a .256 team batting average, the club's lowest since hitting .250 in 1992. The 637 runs scored were the club's lowest since 1988. The 111 home runs were the lowest since 1990.
Adrian Beltre went 1-for-4 on Sunday and finished with a .324 batting average, fourth best in the AL. He also ended up leading the Rangers with 19 home runs and 77 RBIs. It's the first time the Rangers haven't had a player with at least 20 home runs in a full season since 1980 and the 77 RBIs are the fewest by their team leader since 1982.