The Boston Red Sox starting rotation has seen its fair share of injuries this season, but Connelly Early's injury could be a backbreaker. 

Early left Tuesday's outing against the Washington Nationals after feeling discomfort in his left elbow. On Wednesday, the left-hander was placed on the 15-day injured list with left elbow inflammation, far from the positive news interim manager Chad Tracy wanted to hear. 

Tracy was optimistic on Tuesday, saying to Ian Browne of MLB.com after the Red Sox's 8-1 loss to the Nationals, "It's not unreasonable to think that maybe he [Early] misses one [start].”

With Early down, the Red Sox made two roster moves on Wednesday to give them two more arms in their bullpen for the series finale with the Nationals. Left-hander Jovani Moran had been activated from the injured list with left elbow inflammation of his own, which kept him out for nearly a month. 

The other move was rookie left-hander Alec Gamboa getting recalled from Triple-A Worcester. In 21 games with the Red Sox this season, Moran is 1-2 with a 3.00 ERA in 21 games (three starts), while Gamboa has two games (1.2 innings) under his belt. 

The Red Sox' starting rotation could be in for a rough month of July

Heading into a critical month, the Red Sox' starting rotation may be stretched to the limit. With the trade deadline (Aug. 3) fast approaching, the Red Sox will likely be sellers, with at least one starter in the rotation being on the trade block. 

Right-hander Sonny Gray is a likely candidate to be moved before the deadline, but will need to waive his no-trade clause for the Red Sox to do so. 

Early had been one of the Red Sox's best pitchers this season, going 7-5 with a 3.44 ERA in 17 starts. Early and the starting staff entered Tuesday's contest with 12 straight quality starts, two shy of tying a Red Sox franchise record set back in 1988. 

Young left-handers Jake Bennett and Payton Tolle will have to take more of a workhorse mentality to fill the innings that Early leaves behind. Tolle proved he could be counted on to take his game to another level when Gray went down with a hamstring injury, so Bennett will need to show the same gusto in this instance. 

Since his recall from Worcester, Bennett has been solid, posting a 2.78 ERA and 0.88 WHIP in 22.2 innings. Tolle has been even better since becoming a full-time member of the starting rotation, posting a 2.35 ERA and a 0.85 WHIP in May and a 3.00 ERA with a 1.20 WHIP in June. 

Some good news for the Red Sox starting rotation is the possibility that left-hander Patrick Sandoval could return soon. After having two setbacks in his rehab assignment, Sandoval is slated to make another rehab start with Double-A Portland on July 4, per MLB.com.

Sandoval will throw 70 pitches, and it will be determined whether he can return to the big league club or not after his outing.