It’s a shorter deal in length, by perhaps half, than many analysts predicted for Imai when free agency opened after the World Series. It could end up being much shorter, with Imai negotiating opt-outs after each of the first two seasons.

His agent, Scott Boras, has compared Imai’s capabilities to those of Los Angeles Dodgers’ World Series hero Yoshinobu Yamamoto. It does not seem like the rest of MLB agrees with Boras’ vision, which is why Imai, who is 27 years old, is betting on himself with the possibility of returning to free agency next season and the one after. The Chicago Cubs also were said to be interested in Imai but instead reportedly could pivot to someone like right-hander Zac Gallen.

Imai’s deal with the Astros is the most significant free-agent activity in Major League Baseball this offseason since slugger Munetaka Murakami signed with the Chicago White Sox nearly two weeks ago. Not coincidentally, Murakami also had been facing a deadline to sign with an MLB team or return to Nippon Professional Baseball. The signing deadlines are part of the posting process negotiated between NPB and MLB. Murakami’s deal with Chicago, for two years and $34 million, also was shorter and for less money than the consensus of analysts predicted.

A third major free agent from Japan, corner infielder Kazuma Okamoto, remains unsigned with his own negotiation window set to close Sunday at 5 p.m. ET. MLB suitors for Okamoto reportedly include the Toronto Blue Jays, Pittsburgh Pirates, Boston Red Sox, San Diego Padres and Los Angeles Angels.

The dozens of other MLB free agents still unsigned, including some of the biggest names available, have no such restrictions — aside from a soft deadline like the start of Spring Training in February. MLB commissioner Rob Manfred has floated the idea of adding a negotiating window to free agency like other sports with salary caps have done. While such a change in MLB could create a media event that draws more attention to the sport during the offseason, it’s also more likely to put pressure on individual players to “take it or leave it.” Player agents, with good reason, tend to view free-agent signing windows as a way to keep salaries down.

Left-handers Ranger Suárez and Framber Valdez are the best starting pitchers still available in free agency. Recent predictions match Suárez with the Arizona Diamondbacks and Valdez with the Baltimore Orioles. The D-backs, with right-hander Merrill Kelly, and the Orioles with slugger Pete Alonso, already have been active in free agency.

Big-time sluggers also remain unsigned, notably outfielder Kyle Tucker, third baseman Alex Bregman, infielder Bo Bichette and outfielder Cody Bellinger. Recent predictions have Tucker signing with the Blue Jays, Bregman returning to the Red Sox, Bichette moving to the Detroit Tigers, and Bellinger returning to the New York Yankees.