Fans get excited about top prospects because they represent a club's best hope for the future. Some are putting themselves in position to be called up later this summer, others may take longer.
But keeping up with the farm system is part of being a loyal fan, and here are five intriguing prospects to watch in the American League West.
ANGELS
Prospect: LHP Jose Suarez
MLB Pipeline rank: No. 11/NA
Why you should keep an eye on him: Suarez began the season with Class A Advanced Inland Empire, but he's been so dominant that he's already climbed two levels and reached Triple-A Salt Lake. As of Tuesday, the 20-year-old left-hander led all Minor League pitchers with 69 strikeouts over 38 2/3 innings, giving him a 15.8 K/9 ratio on the season. Suarez, who mixes a low-90s fastball with a plus changeup and curveball, has a 2.79 ERA in nine starts between Inland Empire and Double-A Mobile. General manager Billy Eppler praised his advanced feel for pitching, especially with his secondary stuff.
ETA: Suarez could be a rotation option later this summer, if needed.

ASTROS
Prospect: OF Kyle Tucker
MLB Pipeline rank: Astros' No. 2/No. 16 overall
Why you should keep an eye on him: Tucker, who opened eyes when he slugged five homers in Spring Training, is making a nice transition to Triple-A at only 21 years old. Through 42 games at Fresno, the left-handed-hitting outfielder was slashing .289/.360/.457 with five homers and 33 RBIs in 173 at-bats. Houston is lacking production in left field this season, and Tucker could get his shot.
ETA: Later in 2018 if the Astros need the offensive boost.

ATHLETICS
Prospect: C Sean Murphy
MLB Pipeline rank: A's No. 6/No. 97 overall
Why you should keep an eye on him: The Athletics are set with Jonathan Lucroy as their catcher, but he can become a free agent after the season. Murphy, a third-round pick in 2016, is clearly Oakland's catcher of the future, possessing athleticism and plus defensive skills behind the plate. Offensively, he is off to a strong start at Double-A Midland, hitting .312 with a .353 on-base percentage and a .539 slugging percentage.
ETA: 2019, although this season is not out of the question.

MARINERS
Prospect: Kyle Lewis, OF
MLB Pipeline rank: Mariners' No. 1/No. 65 overall
Why you should keep an eye on him: Lewis has been Seattle's premier position prospect since being drafted in the first round (No. 11 overall) in 2016, but major surgery on his right knee following a home-plate collision 30 games into his pro career continues to slow his progress. The 22-year-old made good strides after returning in the second half last year for Class A Advanced Modesto, but another minor surgery to clean up the knee again last offseason delayed his start once more this season. Lewis made his 2018 debut last week. He was at designated hitter the first five games and is just now starting to play in the outfield, while still working to find his timing at the plate.
ETA: This year is just about Lewis getting healthy and re-establishing himself without worrying about climbing the ladder. If all goes well, he could move quickly in the future, with perhaps a full-time shot in 2020 if his bat plays at the upper levels.

RANGERS
Prospect: Julio Pablo Martinez, OF
MLB Pipeline rank: Rangers' No. 3/No. 64 overall
Why you should keep an eye on him: The Rangers signed Martinez in March and he will make his professional debut on June 2 in the Dominican Summer League. He won't be there long. Martinez, 22, was a star in the Cuban National Series before leaving the country, and he should be playing Class A in the United States later this summer. He has excellent speed and makes good contact with some power as a left-handed hitter. Martinez can cover ground defensively in center field.
ETA: Martinez is an unknown commodity, but his success in Cuba suggests he could move quickly through the system. He could be in Arlington by 2020, but next year is not out of the question.