Deciding whether to buy or sell at MLB's July 31 trade deadline is only half the battle. 

The trade deadline is like a "Going Out of Business" sale at a used car lot. You might find the vehicle that carries you for years to come, or you might end up with a lemon that breaks down a few days later.

Which players on floundering teams are most likely to fall into that latter group?

Based on a combination of how a player's predictive stats compare to previous seasons of his career and to the 2021 norms of the league, we've identified eight key players who figure to get moved before the deadline even though a second-half slump looks likely.

Players are listed in no particular order, outside of oscillating between pitchers and position players.

 

Kyle Gibson, SP, Texas Rangers

In his ninth season in the majors, Kyle Gibson has finally emerged as an ace and made it to an All-Star Game.

Despite an atrocious dud on Opening Day (0.1 IP, 5 ER), Gibson entered the break with a 2.29 ERA and a 1.07 WHIP. That's because he went at least five innings and allowed three or fewer earned runs in each of his next 15 starts.

However, his "luck" rates stand out like a sore thumb compared to how he pitched prior to turning 33.

Gibson's BABIP (.254) is more than 50 points below what his career BABIP was at the start of the season. He's been keeping balls in play far more often than he used to, allowing only 0.71 home runs per nine innings pitched. That number was north of 1.0 in each of the previous five seasons, including a 1.60 rate last year.

Gibson had career marks of 4.57 ERA and 1.42 WHIP from 2013-20, but his xFIP hasn't much changed. After seven consecutive seasons in the 3.80-4.50 range, he's currently at 3.89 xFIP. That more or less suggests he should have a second half that looks more like the past few seasons as opposed to the past few months.

Gibson isn't an average deadline target in terms of contract status, either. His salary will go down in 2022, but he's still signed for $7.7 million next season before becoming a free agent the following winter. That's an absolute steal if he pitches like this for another season-and-a-half, but it would be a tough pill to swallow if he regresses to his normal state.

(Note: This was written prior to Monday night's poor start against Detroit. The regression may have already begun in earnest.)

 

Joey Gallo, OF/DH, Texas Rangers

With Joey Gallo, you know you'll be getting a ton of the three true outcomes. He has either homered (24), walked (72) or struck out (112) in 57.8 percent of his 360 plate appearances this season.

That's a preposterously high number for most players, but it's par for the course for Gallo. He had one of the three true outcomes in 57.5 percent of his plate appearances from 2017-20.

There's no point in expressing any BABIP-related concerns with Gallo, since he's liable to put only three or four balls in play in any given week. However, there's a major risk with hoping that Gallo might be the missing piece of a playoff push: His numbers in September and October are particularly unsightly.

In 319 career plate appearances in those two months, Gallo is batting .187/.292/.396 with a strikeout rate of 41.1 percent. By comparison, from April through August, he triple-slashes .217/.337/.521 with a strikeout rate of 35.8 percent.

The 125-point decline in slugging percentage is the biggest problem. You can live with an astronomical strikeout rate if someone is at least homering once in every 14.2 trips to the plate, like Gallo does for the first five months of the year. When that number balloons to once every 21.3 plate appearances in September and October, though, those strikeouts hurt far more.

Granted, 319 plate appearances is roughly a half-season's worth of data points, and more than 12 percent of those stats came in 2015 and 2016 when he was a September call-up who struggled mightily. But Gallo does seem to consistently struggle at the plate late in the year.