Is this the year baseball raises the strike zone? Is it the year the sport does away with the practice of lobbing four balls toward home plate to issue an intentional walk? Major League Baseball has made formal proposals to the players' union to usher in both of those changes, sources told ESPN.com.

Neither of those innovations can be implemented without approval of the Major League Baseball Players Association. The union is currently in the process of feeling out players on the proposed changes, sources said. For either or both to take effect this season, an agreement would have to be reached "sooner rather than later," said one source, because spring training games begin in just two and a half weeks.

MLB's proposal would raise the lower part of the strike zone to the top of the hitter's knees. Since 1996, the bottom of the zone has been defined as "the hollow beneath the kneecap." But data shows that umpires have been increasingly calling strikes on so many pitches below the knees that, if umpires enforce the redefined strike zone, it would effectively raise the zone by an estimated 2 inches.

Barry Bonds receives an intentional walk in 2007. Kyle Terada/USA TODAY Sports

The change in the intentional-walk rule would end the long-standing practice of requiring the pitcher to toss four soft pitches outside the strike zone. Instead, a team could just signify it wants to issue an intentional walk, and the hitter would be sent directly to first base.

Both proposals are part of MLB's attempts to streamline what commissioner Rob Manfred often refers to as "pace of action." But the two changes would have far different impacts.

Getting rid of the old-fashioned intentional walk would eliminate about a minute of dead time per walk. In an age in which intentional walks actually have been declining -- there were just 932 all last season (or one every 2.6 games) -- that time savings would be minimal. But MLB sees the practice of lobbing four meaningless pitches as antiquated, so eliminating them would serve as much as a statement as it would a practical attempt to speed up the game.

The change in the strike zone, however, could have a much more dramatic effect, MLB believes. Its intent is to produce more balls in play, more baserunners and more action at a time when nearly 30 percent of all hitters either walk or strike out -- the highest rate of "non-action" in the game's history.

Neither side is certain yet how players will respond to the new proposals, but sources indicate that the change in the intentional-walk rule is more likely to be approved for this season than the raising of the strike zone. Players have mixed feelings about the redefined strike zone; shrinking the zone helps hitters and hurts pitchers, so if there is a path to a consensus among players, it is difficult for either side to see one developing in the next couple of weeks.

Sources said MLB presented the two proposals to the union in late January, after they were agreed to by both its competition committee and playing-rules committee. If the changes sound familiar, it's because, as ESPN.com reported last May, MLB also felt out the union on both proposals last year, sources said.

However, the players were lukewarm at the time, telling MLB they were open to revisiting the ideas in the future. Now that the two sides have negotiated a new labor deal, they are expected to explore a variety of ideas designed to speed up pace of play.