HOUSTON -- The Astros have broken ties with their Triple-A affiliate, the Fresno Grizzlies, after four seasons, which clears the way for the club to pursue an agreement with the Round Rock Express, which has been the Triple-A affiliate of the Rangers the past eight years.

An announcement on the Astros' Triple-A future could be made later this week. Club officials aren't able to comment on any pending agreements, but Astros president of business operations Reid Ryan, whose family owns the Round Rock Express, said the Astros are going to "survey the market."

The Express and Astros were affiliated with each other from 2000-10, including five seasons as a Double-A team ('00-04). The Express became the Triple-A affiliate of the Rangers in '11, while the Astros' Triple-A affiliation bounced between Oklahoma City and Fresno.

"We really appreciate what [the Fresno Grizzlies], their ownership, management, city leaders and fans have done for the Houston Astros," Ryan said. "They have just treated us great the last four years, but we want to look around because we think there's opportunities to put our Triple-A affiliate closer to Houston, Texas."

Moving their Triple-A operation to Round Rock, which is outside Austin, would put the Astros 170 miles away from their top Minor League affiliate. That would allow players to move more easily between Triple-A and Houston during the season than Fresno, which required a long flight. The Astros' Double-A affiliate, the Corpus Christi Hooks, is also in Texas.

"We had a 10-year history between Round Rock and the Astros," Ryan said. "We're going to see what's out there, and they're at the top of our list, and hopefully we'll have an announcement later this week."

Tucker returns to Astros 

With Fresno having been eliminated by Memphis in four games in the best-of-five Pacific Coast League Championship Series on Saturday, the Astros on Sunday recalled outfielder Kyle Tucker from Triple-A in what is likely their final Minor League callup in September. Houston has 34 players on its active roster.

Tucker, the No. 8 overall prospect per MLB Pipeline, won't play much until the Astros have clinched the American League West title, manager AJ Hinch said. Tucker is making his third appearance on the Astros' big league roster after hitting .332 with 27 doubles, three triples, 24 homers, 93 RBIs and 20 steals in 100 games at Triple-A this year. He has batted .154 (8-for-52) with three RBIs with the Astros.

"Calling Tucker up now is more of a reward for the season he's had," Hinch said. "It's been incredible in the Minor Leagues. We want him to continue to get a little bit of experience. If it's in short spurts now, great. If I can get him some at-bats in the next couple of weeks, that's great for us as a team and great for him as a player. He's part of our future, and once the [Triple-A] season ended, it was a pretty easy decision to bring him back."