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Pitchers and catchers will begin reporting to spring training camps in Arizona and Florida next week. The offseason is almost over, in other words. Whenever a chapter closes, be it a season or in life, it's worth some reflection. With that in mind, below we've highlighted four moves (or clusters of moves) that we believe did not receive proper appreciation when they were made this winter.

Here are the four best under-the-radar moves of the winter.

1. Hunter Renfroe, Red Sox

From a surface-level perspective, Renfroe had a horrible year for the Rays in 2020. He hit .156/.252/.393 during the regular season, then struck out in 11 of his 24 postseason plate appearances. The Rays shooed him away early in the offseason, but former Tampa Bay exec Chaim Bloom welcomed him to a different AL East locale with a one-year deal worth $3.1 million. Splash around a little, and it's easy to find reason to believe Bloom and the Red Sox will get more than their money's worth.

Renfroe is known for his streakiness, but elements of his game have remained static for years. His exit velocity has consistently fallen between 89.4 and 89.9 mph the last three seasons; his launch angle has stuck in a tight cluster, too; and last season, he even improved upon both his strikeout rate (down from 31.2 percent to 26.6) and walk rate (up to 10.1 from 9.3). Had his topline numbers been in line with his career marks (or thereabout), some team might've seen him as a player on the rise who was worthy of the Avisail Garcia contract (two years, $20 million).

To recap: Renfroe hit the ball as hard, and about on the same trajectory, as he did when he posted a 111 OPS+ the previous two seasons. He also struck out less often than he had in 2019 and walked more than he ever had. Maybe there's something we're missing, but that makes him a reasonable bounce-back candidate to us.

2. Robbie Grossman, Tigers

Whereas what makes us hopeful about Renfroe is that he appears to be the same hitter as before, what makes Grossman (two years, $10 million) appealing is that he appears to be a different hitter than he was prior to the 2020 season. 

We summed it up earlier this winter, when we ranked Grossman as the 33rd-best free agent:

Grossman made the most of the truncated year, transforming himself from a low-wattage, walks-only hitter into someone whose isolated slugging (.241) was higher than his previous season's batting average (.240). His gains in exit velocity, launch angle, and power output don't appear to be the result of a small sample; rather, they're the product of him adding a leg kick and becoming more pull-happy (from 29.2 percent in 2019 to 46.1 percent in 2020). Presuming some of that sticks, Grossman ought to appeal to teams as a low-cost, switch-hitting option who can handle either corner-outfield spot or the designated hitter role.

Contenders didn't buy in, at least not to the extent the Tigers did. We'll see who was right soon enough.

3. The Giants go slider-heavy

Identifying patterns in player acquisition behavior is often one-part overthinking it and two-parts oversimplifying things. That established, the Giants sure seemed to have a type this winter. They added Anthony DeSclafani, Matt Wisler, and John Brebbia, all pitchers who possess quality sliders.

To break down each:

  • DeSclafani introduced a new slider last season, one with added depth. It didn't prevent his fastballs from getting torched, but he had a good deal of success with his new breaking ball and he should throw it more frequently.

  • Wisler is the poster pitcher for chucking the breaker more frequently. He threw his slider more than 80 percent of the time last year, and had a career season in the process (1.07 ERA, 12.4 strikeouts per nine).

  • Brebbia will miss most of the season because of Tommy John surgery. In 2019, his slider coerced whiffs nearly a third of the time, and opponents batted all of .169 against it.

Again, the Giants' thinking surely wasn't as simple as "sign the best sliders," because they also added Kevin Gausman and Alex Wood, neither of whom is slider-dependent, and they shipped out Shaun Anderson, who would fit in said plan. 

That established, the three slider artists San Francisco did land came at a combined cost of less than $9 million. Presuming the Giants have those three play to their strengths, they're unlikely to regret their investments. 

4. Marlins make underrated bullpen adds

We'll end with the Marlins, whose offseason activity was contained to the bullpen. The Fish could have as many as five new faces in relief, including two highlighted here -- Anthony Bass and Ross Detwiler -- who signed for a combined $5.85 million.

We covered why we're believers in Bass when we ranked him as the 60th-best free agent available this winter:

Players who suit up for eight organizations before celebrating their 33rd birthday seldom reach big-league free agency, let alone rank in the top 60. Bass is the exception. Over the last three seasons, he's compiled a 127 ERA+ and a 2.69 strikeout-to-walk ratio in 89 innings; the comparison isn't perfect for a few reasons, but Daniel Hudson received a multi-year deal in winter 2019 after posting a 139 ERA+ and a 2.56 strikeout-to-walk ratio in his previous 119 frames. Bass is reliant upon two pitches, a mid-90s fastball and a swing-and-miss slider, yet he's been effective versus lefties and righties alike throughout his career. He's also an extreme groundball pitcher whose sweet-spot percentage was the best in the majors; in other words, almost all of the contact he allowed was either hit into the earth or popped up. That'll play.

As for Detwiler, it's easy to dismiss him because of his career to date. He turns 35 in March and he has a 90 ERA+ in more than 670 big-league innings. Even his success last season came in 19 innings, and with a poor strikeout rate (6.9 per nine). If there is one good reason to give him another look, it's a rebooted slider that held opponents to a .208 average and generated 34 percent whiffs.

If the Marlins ask Detwiler to crank up his slider usage in 2021, he might be on the cusp of remaking his image.