SEATTLE -- With the July 31 Trade Deadline rapidly approaching, talk turns to what moves might be made to help clubs and whether teams will be buyers or sellers.

Like every franchise, the Mariners have made their share of midseason moves over the years. Some have helped, some have hurt, and usually it takes several seasons to find out which way a trade will turn.

Top in-season deals

Here are the Mariners' five best in-season trades:

1. May 25, 1989: The Mariners acquired pitchers Randy Johnson, Brian Holman and Gene Harris from the Expos for pitchers Mark Langston and Mike Campbell.
While Langston was Seattle's best pitcher and a one-time All-Star during his six seasons with the Mariners, he was about to become a free agent in 1989, when the club dealt him to Montreal for a trio of young arms.

One of those turned out to be the long left wing of Johnson, who developed from a wild, hard-throwing prospect into one of baseball's premier pitchers in 10 seasons with the Mariners. He was a five-time All-Star and a Cy Young winner while with Seattle, a huge part of turning the franchise into a playoff team in 1995 and beyond, and now a member of the Mariners Hall of Fame.

Holman won 32 games in three years as a starter for Seattle, as well, while Harris pitched four seasons for the Mariners, primarily in relief. Langston opted for free agency and signed with the Angels the following year.

2. July 21, 1988: The Mariners acquired outfielder Jay Buhner and pitchers Rich Balabon and Troy Evers from the Yankees for first baseman Ken Phelps.
Buhner was a 23-year-old with limited experience when he arrived in the Northwest, but he wound up playing 14 years for Seattle and becoming a Mariners Hall of Famer who hit .255 with 307 home runs and 965 RBIs and played an outstanding right field for some of the best teams in franchise history.

Phelps hit .240 with 17 homers in two seasons with the Yankees. This turned into such a disastrous trade for the Yankees that it was immortalized in a "Seinfeld" episode.

3. July 30, 1996: The Mariners acquired left-handed pitcher Jamie Moyer from the Red Sox for outfielder Darren Bragg.
When they acquired him, Moyer was a 33-year-old journeyman with a 66-77 career record for six different clubs. He went on to pitch 11 seasons in Seattle, while compiling a 145-87 record with a 3.97 ERA.

Bragg spent three seasons in Boston and went on to have a solid career, playing with seven more clubs before retiring in 2004. But Moyer became the Mariners' all-time career wins leader and posted a pair of 20-win seasons during a decade of excellence, while becoming one of baseball's most-intriguing pitchers with his array of effective off-speed offerings.

4. July 31, 1998: The Mariners received pitchers Freddy Garcia and John Halama and shortstop Carlos Guillen from the Astros for pitcher Randy Johnson.
Although Seattle gave up one of the greatest left-handers in baseball history, the Big Unit was in the final year of his contract and about to become a free agent at that time.

The expectation was that Johnson was intent on signing with the D-backs, which he wound up doing after pitching two months and helping the Astros reach the playoffs. The three young prospects received back for Johnson all developed into key players on some outstanding Mariners teams, including the club that won 116 games in 2001.

5. Aug. 15, 1995: The Mariners acquired outfielder Vince Coleman from the Royals for pitcher Jim Converse.
Seattle never had been in the rent-a-player category much in franchise history until the 1995 season, when the Mariners made a huge late-season run to qualify for their first postseason berth. Coleman, a 33-year-old veteran, played only 40 games for Seattle, but he provided a key spark down the stretch in that last month and a half of '95, while hitting .290 with 10 doubles, two triples, a home run and 16 stolen bases with 27 runs scored.

Coleman signed with the Reds in free agency the following year. Converse pitched 12 games in relief for the Royals over the next three years and was released.