Week 15 Fantasy Baseball Waiver Wire: Noelvi Marte, Colt Keith, Brooks Baldwin Lead Infielders

A look at the latest fantasy baseball risers across catcher and infield positions, featuring breakout bats, injury replacements, and deep-league waiver wire gems to watch heading into the second half of 2025.

Chicago White Sox Outfielder Brooks Baldwin / Gregory Fisher-Imagn Images

With the MLB season heating up, fantasy managers are scrambling for infield help—and this week’s crop of catchers, corner bats, and middle infielders offers a mix of red-hot breakouts and under-the-radar stashes.

Catchers

Victor Caratini, Houston Astros

Halfway through this week, Caratini already has a run, one home run, and four RBIs over nine at-bats (.333) while remaining in about two-thirds of the free agent pools in 12-team leagues. Over the past 17 days, he went 11-for-42 with five runs, four home runs, and 12 RBIs with no walks and 11 strikeouts. He fits the C2 profile in deep formats while continuing to be a short-term option in shallow leagues.

Francisco Alvarez, New York Mets

Francisco Alvarez puts us in front!

It's Alvy's third straight game with a home run! pic.twitter.com/JS9A51LbO7

— Syracuse Mets (@SyracuseMets) July 2, 2025

Over his last five games in the minors, Alvarez went 7-for-20 with four runs, three home runs, and six RBIs while taking no walks and whiffing six times. Unfortunately, making contact has been an issue at AAA (12 strikeouts over 38 plate appearances – 34.2%). Most fantasy teams have kicked him to the curb over the last week, making him a free agent in over 60% of 12-team leagues in the high-stakes market.

Adrian Del Castillo, Arizona Diamondbacks

After missing 10 days with a back issue at AAA, Del Castillo extended his hitting streak to seven games (7-for-24 with seven runs, one home run, and six RBIs). He now has 21 rehab games in between Arizona’s rookie complex and AAA, leading to a .306 batting average with 23 runs, five home runs, and 19 RBIs.

With Gabriel Moreno out, Del Castillo may get another shot with the Diamondbacks. He hit over .300 last year at AAA and the majors with 30 home runs and 94 RBIs.

First Basemen

Colt Keith, Detroit Tigers

The injury to Kerry Carpenter this week could be the window Keith needs to finally get every day at-bats. The Tigers continue to hit him at the top of their batting order when he is in the lineup, helping his counting stats. Keith’s riding a six-game hitting streak (9-for-21 with five runs and two RBIs), but he must hit balls in the seats to help fantasy teams.

In 2023, Keith hit .306 over 507 at-bats between AA and AAA with 88 runs, 27 home runs, and 101 RBIs, showcasing his future potential in power. He should be a free agent in close to 60% of 12-team leagues.

Christian Encarnacion-Strand, Cincinnati Reds

A MONSTER GRAND SLAM FROM CHRISTIAN ENCARNACION-STRAND 🤯 pic.twitter.com/iykzYVPGRY

— MLB (@MLB) July 3, 2025

The first half of 2025 has been frustrating for Encarnacion-Strand supporters. His stats over his first 126 at-bats (13 runs, six home runs, and 19 RBIs) projected over 500 at-bats would be competitive in home runs (24) and RBIs (76) while lowering his strikeout rate (22.6). He’s riding a three-game hitting streak (4-for-12 with three runs, one home run, and four RBIs) while being banished to the bottom of the Reds lineup.

Cincinnati released Jeimer Candelario over the past week, which should improve Encarnacion-Strand’s opportunity over the second half of 2025. For fantasy teams looking for home runs, he’s knocking on your door in about 50% of 12-team leagues.

Second Basemen

Tyler Fitzgerald, San Francisco Giants

The Giants have given Fitzgerald 191 at-bats to prove himself this year, but he only hit .225 with 17 runs, two home runs, 12 RBIs, and nine stolen bases. As a result, the fantasy market surrendered him to the free agent pool over the past month or so.

In 2024, Fitzgerald jockeyed between AAA and the majors with a minimal opportunity (21-for-76 with 12 runs, one home run, six RBIs, and seven steals) until the second week in July. Over his next 49 games with 193 at-bats, his bat (37 runs, 13 home runs, 25 RBIs, and 10 steals) helped fantasy teams move up the standings.

Over the past week, San Francisco placed Christian Koss and Casey Schmitt on the injured list, almost forcing them to ride Fitzgerald. His combination of speed and power is intriguing, but he must make more contact to be a fantasy asset over the second half of the year.

Thairo Estada, Colorado Rockies

Over his last six starts, Estrada has three hits in four different games, leading to a .462 batting average over 26 at-bats with two runs, one home run, and eight RBIs. He’s hitting well in the season (.317 over 101 at-bats), but his runs (8), home runs (2), and stolen bases (1) haven’t moved the fantasy needle. The Rockies play six games on the road next week (@BOS and @CIN). Estrada is rostered in about half of 12-team leagues.

Third Basemen

Shay Whitcomb, Houston Astros

SHAY WHITCOMB! FIRST MAJOR LEAGUE HOMER! #BuiltForThis pic.twitter.com/zHfQUuIXnS

— Houston Astros (@astros) July 3, 2025

Over the past month, I’ve been tracking Whitcomb in my AL-only due to his intriguing 20/20 skill set at third base. Houston recalled him this week after Jeremy Pena went on the injured list. He hit his first major league home run in Colorado on Wednesday night while going 1-for-4. The Astros gave him only 57 at-bats over the past two seasons (.175 with two runs, one home run, six RBIs, and 14 strikeouts).

Whitcomb has excelled at AAA (.288/116/44/134/32 over 645 at-bats), which should make him a player to follow in case the Astros give him starting at-bats. His best chance for playing time could come at DH or left field. He is more viable as a flier player in deep formats.

Noelvi Marte, Cincinnati Reds

The Reds activated Marte off the injured list on Friday. Over his nine rehab games between Cincinnati’s rookie complex and AAA, he hit .333 over 30 at-bats with six runs, two home runs, and 11 RBIs while taking six walks and striking out once. Marte shined earlier in the year in the majors (.294/10/3/17/4 over 68 at-bats), making him an attractive waiver wire add if he somehow slipped through the free agent cracks.

Shortstop

Brooks Baldwin, Chicago White Sox

Brooks Baldwin had the clutch Home Run in the top of the 10th! pic.twitter.com/vivkNuFdyz

— Charlotte Knights (@KnightsBaseball) June 25, 2025

The White Sox have played Baldwin at three positions (2B, SS, and OF) this year, creating more value to fantasy teams that favor multi-position players. His play has been disappointing over the past two years with Chicago (.208/18/5/24/6 over 250 at-bats) due to a weaker approach (14 walks and 75 strikeouts). Baldwin went deep on Thursday night (2-for-3 with a run and two RBIs), which may lead to more starts.

He has been a beast over 28 games after his demotion back to AAA, leading to a .368 batting average with 27 runs, 11 home runs, 24 RBIs, and four stolen bases over 114 at-bats. The White Sox called him up (7/1) after Luis Robert went on the injured list. I like his future profile, and he has a chance to help fantasy teams if Chicago commits to his bat over the last three months. Baldwin should be a free agent in almost all leagues.

Other Fantasy Baseball News

Week 15 MLB Prospect Watch: Francisco Alvarez, Shay Whitcomb Lead Infielders

Week 15 MLB Prospect Watch: Luis Matos, Esteury Ruiz Lead Minor League Outfielders

Week 15 MLB Prospect Watch: Joe Boyle Surges While Logan Henderson, Bubba Chandler Fade