The Los Angeles Dodgers visited the Boston Red Sox last weekend, winning two out of three. The series marked the return of Mookie Betts to Fenway Park for the first time since Boston traded him away in 2020.

The beloved former—and possibly future—MVP received a warm ovation from the crowd and he responded in kind by saluting them back. After observing all the niceties, Betts showed no mercy. He went 7-15 in the three-game set with a home run, two doubles, and a walk. On defense, he played both second base and right field in each game.

The series reminded Boston of who they let slip away. They dealt him to the Dodgers a year before his free agency when he rebuffed a reported $300 million extension. Before he reached the open market, he agreed to a 12-year, $365 million deal to remain in Los Angeles.

This year, in which Betts leads the NL with 7.4 WAR on Baseball-Reference, he has played 92 games in right field, 47 at second base, and 16 at shortstop. His defensive versatility stands in contrast to the holes in the Red Sox lineup this season, especially at some of those positions.

Christian Arroyo has gotten the lion’s share of playing time at second base this season for the Red Sox, suiting up for 62 games and 442 innings. However, the club designated him for assignment on August 4. He’s on the Triple-A Worcester Red Sox roster at the moment. In 206 plate appearances with Boston, he slashed .241/.268/.369. His 70 OPS+ indicated his offense was 30% worse than league average.

Their second most frequently-used second baseman has been Enmanuel Valdéz, though he was sent down to the minors in early June. He accumulated 244 innings over 32 games at the position, but hit only .234/.280/.404 with an 82 OPS+.

On the current roster, Pablo Reyes has the most experience this season at second, playing 24 games and 159 innings. He has a lofty .303 batting average based on an excellent 85.7% contact rate, but he rarely walks or hits for power. It’s unlikely he can keep his batting average that high for much longer.

Altogether, Boston has used nine different players at second base this season. This is tied for the most of any MLB team—as luck would have it, the Dodgers are the other club who have deployed nine different second basemen.

Ironically, Boston’s primary shortstop this season now wears Dodger blue. Kiké Hernández played 64 games and 484 innings for the Red Sox at short before they traded him to Los Angeles on July 25. At the time of the trade, he was hitting .222/.279/.320 with a 61 OPS+. Since the move, he improved to .275/.323/.451 with a 107 OPS+.

Prior to last season, the Red Sox signed Trevor Story to a six-year, $140 million contract, but declining arm strength forced him to play second base exclusively in 2022. It turned out that his arm problems were injury related, and offseason Tommy John surgery kept him out of action until August 8. He has played 101 innings over 12 games since then.

Yu Chang’s 256 innings at short are second on the team behind Hernández, but he’s in Triple-A because he batted only .162 over 112 plate appearances. Reyes has also spent 193 1/3 innings at the position. Just like second base, they have played nine different fielders at shortstop this season, which is more than any other MLB club.

The right field picture isn’t as bleak for the Red Sox as their middle infield spots. Alex Verdugo has primarily manned the position, batting a healthy .278/.342/.446 with a 111 OPS+. He was the main player Boston acquired from the Dodgers in the Betts trade and has 3.6 WAR this season.

That being said, he’s no substitute for Betts, who leads the league with a .611 slugging percentage and 171 OPS+. He also has six Gold Gloves in right field. No position player in MLB has been more valuable this season according to WAR. (Shohei Ohtani’s 9.9 WAR is the top overall figure, which is the sum of 5.9 as a hitter and 4.0 as a pitcher.)

The Red Sox are 69-62, fourth in the AL East and 2.5 games out of a Wild Card spot. They lack star power on their roster aside from third baseman Rafael Devers. Betts would’ve made the difference between a decent, forgettable team and a World Series contender, if only they’d had the foresight to keep him.