The Rays moved to 6-1 on the current homestand while ending the Astros' road-winning streak at 11 games.
Font pitched five scoreless innings, not allowing a hit until a two-out double in the fifth by Max Stassi. He then walked Jake Marisnick to start the sixth and fell behind, 3-1, to the next batter, Alex Bregman. That's when Rays manager Kevin Cash and a trainer made a mound visit. A moment later, Cash signaled for right-hander Diego Castillo to enter the game.
"Command was good tonight," Font said. "The last two guys, I don't feel like I can throw the ball where I want to throw."
Font will be examined further Saturday morning.
Font "gave us a huge boost," Cash said. "Got us deep in the ballgame. He was going to continue going, but we'll get him back healthy here soon."
Castillo surrendered a two-run homer to Bregman, with one of the runs charged to Font, whose final line was the one run, one hit, two walks and three strikeouts in five-plus innings.
Font earned his second win of the season, moving to 2-1 with a 1.67 ERA in nine appearances with the Rays, compared to 0-2 with a 12.71 ERA in 10 appearances with the A's and Dodgers before Tampa Bay acquired him in a May 25 trade with Oakland. The Rays moved him over to the third-base side of the rubber, and the adjustment seemingly has worked wonders.
The Rays "trust me and they trust what I can do," said Font, who was the 2017 Pacific Coast League Pitcher of the Year for the Dodgers' Triple-A affiliate in Oklahoma City. "And I feel like I was last year in Triple-A, the command is there."
The Rays scored all three of their runs in the fourth, taking advantage of two errors by Houston. Daniel Robertson's infield single opened the inning, and Joey Wendle followed with a single through the left side against a shifted Astros infield that moved Robertson to third. Adeiny Hechavarria then hit a deep fly ball that Marisnick could not handle as he banged into the center-field wall, allowing Robertson to cruise home and give the Rays a 1-0 lead.
SOUND SMART The Rays reached the halfway point of the season Friday night with a record of 40-41. Of those 81 games, 43.2 percent have been decided by a run, with the Rays improving to 15-20 (.429) in one-run games this season, including 5-1 in their last six one-run games.
NICE MOUNDWORK The Rays have pitched to a 0.75 ERA over their last four games. They have yielded two runs or fewer in all four games, tied for the second-longest such streak in club history (last April 15-19, 2016).
HE SAID IT "Good question. I can't answer. We'll have some more openers and bullpen days -- yippee." -- Cash, on if the Rays just weren't meant to have starting pitchers this season
UP NEXT Ryne Stanek will start Saturday when the Rays host the Astros in a 4:10 p.m. ET contest at Tropicana Field. Stanek is riding an 11 appearance scoreless streak, spanning 14 2/3 innings. Right-hander Justin Verlander gets the ball for the Astros.
Bill Chastain has covered the Rays for MLB.com since 2005.