Fantasy Baseball Overvalued and Undervalued – Week 1

It’s really tough to call any fantasy baseball players overvalued or undervalued only four or five games into a season. No team has played more than six games, and sample sizes are absolutely tiny compared to what we normally need to make long-term judgments on players.

However, based on early performance, team usage, and changes to a player’s approach or mechanics, it’s already clear some players were undervalued in fantasy baseball draft rooms while others may have been overvalued. We can make moves now and help our teams for the whole season.

This weekly piece will look at the past seven days of fantasy baseball performances to see who should be considered overvalued and undervalued going forward. When necessary, I will reference Mick Ciallella’s Fantrax top 400 rotisserie rankings for the 2026 fantasy baseball season.

Undervalued Players

Brendan Donovan (2B/SS/OF – SEA)

Why was Brendan Donovan batting leadoff against the Yankees on Monday night so significant? Donovan has hit leadoff in all but one game this year. The Mariners faced a lefty on March 28, and Donovan (a left-handed bat) hit sixth that game. But he went two-for-five with a stolen base, so the next time the Mariners faced off against a lefty (Monday night), Donocan was back in the leadoff spot and got another hit.
Donovan’s early regular-season success follows a red-hot spring training where he batted .413 with a 1.034 OPS in 46 at-bats. Now he is hitting .412 with two home runs and a 1.369 OPS heading into Tuesday.

https://twitter.com/BarnHasSpoken2/status/2037355180170051792

After being acquired from the St. Louis Cardinals in a three-team trade in February, the Mariners immediately installed him as the leadoff man, which was a struggle for the team in 2025. This leadoff status has allowed him to set the tone for the lineup and have a smashing start to the year.

Jake Burger (1B – TEX)

Jake Burger is a top-12 hitter through the first few games of 2026 and has eight hits and two home runs through four games. His power has never been in doubt, as his bat speed and barrel rate were both over the 85th percentile in MLB in 2025. All he needed was some good fortune in health and a full-time role. So far, he has them.

Seeking to avoid the injury problems that limited him to 103 games in 2025, Burger adopted a new offseason regimen that included Pilates and weight management. This has helped him maintain his powerful swing and stay more consistent. Following the trade of Nathaniel Lowe, Burger was named the everyday starter at first base. This clear role and the security of a new one-year, $3.2 million contract allowed him to focus entirely on his hitting during Spring Training.

Randy Vasquez (SP – SDP)

Due to injuries in the San Diego rotation, Randy Vasquez got a bump to the first five and did not disappoint in his first start. Vasquez struck out eight over six innings over the weekend and now has just a 0.83 ERA. In his debut, he generated 13 whiffs and 8 punchouts, a total he exceeded only once in 28 starts during the 2025 season.

A Randy Vasquez 80-Grade 4-Seam fastball v. Matt Vierling:

95.4 mph
19.1” iVB
7.8” horizontal break
2561 rpms
6.2 vRel pic.twitter.com/M4THyitU9M

— Clark Fahrenthold (@CFahrenthold11) March 29, 2026

After averaging about 93 mph on his four-seam fastball in 2025, Vasquez entered 2026 averaging 95-96 mph in spring. This new velocity has made his primary heater an above-average weapon that hitters can no longer easily drive. He has focused on his four-seam fastball and sinker, and the dividends are paying off after one start.

His next start will be against the Boston Red Sox, who have scored more than three runs just once in their first four games.

Overvalued Players

Josh Naylor (1B – SEA)

We have found the 2026 version of Rafael Devers’ horrific start from 2025. If you recall, Devers started 0-for-16 last season, before catching fire and finishing with an amazing season. Josh Naylor is 0-for-15 to start the season. Will he have a Devers-esque turnaround, too?

That's 7 groundouts in a row from Josh Naylor to start the season

— Steve (@MarinersSteve) March 28, 2026

There were a lot of signs pointing to a Josh Naylor regression this year. He had a career .315 BABIP last year (career .287). He stole 30 bases (and had 25 in his career before that season). His projected slugging percentage was almost 30 points lower than his actual number.

He will rebound at some point, but I wouldn’t come close to expecting 20 home runs, 30 steals, and a .295 average like in 2025.

Nick Kurtz (1B – ATH)

Through his first 17 plate appearances, Nick Kurtz has already struck out eight times (47%), failing to make consistent contact on pitches outside the zone. He also had a slow start to Spring Training, batting just .156 as he worked on pulling the ball more frequently to increase his home run output. That has not materialized yet, and Kurtz doesn’t look like the player who won the AL Rookie of the Year.

After 36 home runs in his rookie season, opposing pitchers are now attacking his weaknesses and getting him to swing and miss a lot in the early season. It’s way too early to count out Kurtz for the season, but it just shows that an early second-round price tag for the first baseman was always a bit of a stretch.

Carlos Estevez (RP – PIT)

Carlos Estevez was everyone’s poster child for regression among relief pitchers in 2026, and for good reason. He led the league with 42 saves with a 2.45 ERA in 2025, but that’s about where the good news ends. Estevez struck out fewer than eight batters per nine innings. He walked three batters per nine, and his expected ERA was 3.69

Add in the fact that the Royals have decided to move in the outfield walls in Kauffman Stadium, and this park is about to play a whole lot more friendly to hitters than it has in the past. A no-strikeout, fly-ball pitcher like Estevez is likely to be most negatively impacted.

Literally adding injury to insult, Estevez took a line drive off the leg this weekend, and the team is now considering a possible IL stint. There might be an ugly 20 saves later in his profile, but there is also the chance he loses the job with this injury.