BOSTON -- As he continues working the phones in the lead-up to Wednesday's trade deadline, New York Yankees general manager Brian Cashman said Friday that he has discussed potential moves with every big league team -- except one.

"I'm fully engaged with every team," Cashman said, "except for the Boston Red Sox."

Fitting comment, considering the Yankees are in the middle of a four-game set with their rivals at Fenway Park. Boston won the opening meeting with a 19-3 beatdown Thursday and followed it up with a 10-5 win Friday.

It was during that opening blowout that starting pitcher Masahiro Tanaka became the first Yankee in nearly 100 years to allow 12 earned runs in a single outing. Carl Mays gave up 13 runs in a start against Cleveland on June 17, 1923, the most by a Yankees pitcher since ERA was first tracked in 1913.

Tanaka's rough outing served as a reminder of the Yankees' need to shore up their pitching before the deadline.

Overall, Yankees starters allowed 40 runs over their previous five games entering Friday. According to the Elias Sports Bureau, that's the most runs allowed in a five-game span within a season since the 2008 Rangers. The previous time the Yankees did it was in July 1912.

"We've entered this process with the deadline with a pretty good feel of what we'd like to do, what we're willing to pay for, and also having the built-in discipline of walking away if we can't find the right matches in any of those circumstances," Cashman said before Friday's game. "That's regardless of what's been happening in the past week."

Cashman reiterated his desire to focus on adding arms ahead of the deadline, if possible.

"I'm looking at pitching, both rotation and pen," said Cashman, who addressed reporters near the visitors' dugout at Fenway Park. "Don't really see much, if anything, on the position-player side to be dealing with. Our main focus is pitching and seeing if there are any matches on the pitching front."

Clearly, those matches have yet to materialize. Cashman hinted at the fact that might have to do with the comparatively high asking prices potential trade partners have floated.

Asked, then, whether any of his minor league prospects were considered "untouchable," Cashman said they weren't, but he did acknowledge a tier existed.

"Some are more realistic than others. So if you're going to play in certain waters, there's only going to be a smaller category of legitimate options that I would be interested in on certain guys," Cashman said.

Among the most-rumored high-value minor leaguers the Yankees might be forced to trade, outfielders Clint Frazier and Estevan Florial and pitcher Deivi Garcia headline the list.

Cashman said the goal in these next five days is to "reinforce our club and add to it if possible." He is also well aware, however, that making a move might not happen.

"So our fallback clearly would be to maintain what we have on our current roster," he said.

That also means holding out hope he'll be able to utilize the pitchers the Yankees have rehabbing through various injuries (Jonathan Loaisiga, Dellin Betances, Jordan Montgomery and Luis Severino).

Three of the four missing arms could be starters once they get fully healthy later this season. One of them, Severino, could pitch both as a starter and out of the bullpen, depending upon where the Yankees are in their playoff push and how Severino has advanced through the later stages of his rehab.

"We'll be able to stretch him out to some degree. To what level that is -- is it 45 pitches? Seventy-five pitches? One-hundred pitches? That remains to be seen," Cashman said. "But as long as his rehab gets completed, he's going to be a legitimate option at some point for us to deploy."