The first time Portland Sea Dogs pitcher Kutter Crawford saw the umpire waiting for him, he briefly wondered why.

“It was definitely new. Coming off the mound, you’re not used to someone asking for your hat, your glove, your belt,” Crawford said last week at Hadlock Field.

“Something you got to get used to. I guess it’s part of the game now.”

The latest addition to the game of baseball is not a new rule change, but the aggressive enforcement of an old rule. Pitchers are not allowed to apply foreign substances to the baseball. Since June 21, umpires have been checking pitchers as they come off the field to search for any forbidden substances.

“They check your hat, glove and have you turn your belt in. Nothing too crazy,” said Sea Dogs pitcher Josh Winckowski. “At the end of the first inning you get checked, and somewhere in the third or fifth, you get checked. … I never used sticky stuff myself, so it’s not much of an issue.”

While the new enforcement has made headlines at the major league level, it’s also being carried out for minor league teams like the Sea Dogs. Some pitching prospects are having to make adjustments or risk ejections and 10-game suspensions, just like the major leaguers, if caught with illegal substances.

“There are going to be guys who were using (substances) who are on notice,” Sea Dogs pitching coach Lance Carter said. “Everyone knows they’re being checked. It’s going to be an adjustment to them.

“We’ll see how it plays out going forward. For me, let’s just play baseball.”

The illegal substances range from sunscreen and pine tar to the trendiest of goops – Spider Tack, a sticky substance developed to help weightlifters. Using the illegal substances was an unofficially accepted practice; everyone wants a pitcher to have control, including the batter who fears a 99 mph fastball coming at his head.

But the substances also can increase the spin rate of pitches, providing more movement on fastballs and curves and making it more difficult for batters. With pitchers becoming more dominant in recent years, Major League Baseball warned teams during spring training that illegal substances had become an issue. By early June, with the league-wide batting average a record low .236, officials announced they soon would step up enforcement. Now pitchers can only rely on rosin bags, a decades-old tradition, in order to get a better grip on the ball.

Every Boston Red Sox minor league team (and their opponents) records the spin rate of pitchers.

“Spin rate is an important piece when evaluating pitchers (and) grading pitches,” said Brian Abraham, director of player development for the Red Sox, the parent club of the Double-A Sea Dogs. “But it’s not necessarily something we would evaluate a pitcher or pitch on alone. … Different pitchers have different spin rates – some pitchers are better at higher spin rates and others at lower.”

Abraham said the sample size is too small to determine how much of a difference has been made from the enforced ban on illegal substances.

“Obviously, substances could alter spin rate, but other factors may as well,” he said. “I definitely can’t speak for other teams or leagues, but we feel like our pitchers have been able to continue to pitch effectively and consistently under the current set of rules.”

Sea Dogs shortstop Ryan Fitzgerald keeps track of opposing pitchers and also notes their spin rate.

“I have a file in my head,” he said. “I’m super big on tracking and technology.”

And since the ban has been rigidly enforced …

“I definitely see a difference,” Fitzgerald said. “I don’t notice it so much on the breaking balls but on the fastballs, for sure. These guys with higher spin rates, the ball is going to look like it’s rising; it’s not, but based on how fast it’s spinning, it makes it look like it’s rising. I don’t see as much of that now as I have in the past.

“In the offseason I was batting against some college guys who were experimenting. An at-bat (against a pitcher without a substance) had a spin rate around 2200-2300. Then they put on some Spider Tack or pine tar or whatever and, off of a sudden, it’s 200 RPMs faster. That makes 91-92 (mph) look like 93-94, sometimes 95. It’s a big difference.”

On the major league level, scoring has increased slightly in the three weeks since enforcement was stepped up. Teams averaged 4.64 runs per game during that span, compared to 4.42 runs on average before June 21.

Not surprisingly, pitchers who relied heavily on substances have been struggling. Since MLB announced on June 3 that it would be cracking down on foreign substances, Red Sox starter Garrett Richards has seen his earned run average spike from 3.75 to 4.91.

“As soon as I get to the field, I put sunscreen on. Well, now I can’t do that,” Richards said after a start in Atlanta on June 16, when he allowed four runs in four innings. “The only thing that’s provided is the rosin bag on the back of the mound which, to be honest with you, is completely useless.”

Red Sox pitching coach Dave Bush said Richards is “struggling to make the adjustment.”

“Across baseball, some guys have struggled with it more than others,” Bush said. “But, in some ways, it hasn’t been as big a deal as I thought it would be.

“We can look at spin rate … and see it may not all be the same. But the performance has been pretty good for our team and across baseball.

“Yeah, some offensive numbers have gone up a little. But I don’t think it’s been a huge, dramatic shift. Look, it’s an adjustment guys have to make. They have to learn how the ball feels in their hand and they may have to grip a little bit differently and shape pitches differently but they’re really talented players. … They have the ability to make adjustments on the fly.”

No pitchers on the Sea Dogs or in their league (Double-A Northeast) have been busted for using foreign substances. Since the increased enforcement, suspensions have been handed out to four minor league pitchers (all in Class A, two affiliated with the White Sox, the others with the Giants and Rangers) and one major league reliever (Seattle’s Hector Santiago).

Checking minor league pitchers should eventually prevent widespread problems in the majors.

“Might as well start now, right?” said the Sea Dogs’ Crawford. “That way you won’t get caught by surprise up there.”

Enforcing the foreign substance ban may help developing pitchers. Frank Gonzales is pitching coach for the Hartford Yard Goats, who completed a six-game series in Portland on Sunday. Gonzales pitched 11 years in pro ball and has coached for nearly 20 years. His son, Marco, pitches for the Seattle Mariners. Frank Gonzales said pitchers can get better by not relying on substances.

“You know what? Honestly, because our guys are focused on pitching, our pitch execution and numbers have probably improved since we’ve gotten rid of some stuff,” he said.

“Pitching still works, you know? I think (the increased enforcement) is smart.

“The rosin bag has been around since I pitched, and it’s going to be around. It will get sticky. I think rosin is a sufficient tacky substance that can definitely aid in grip. So, we shouldn’t have any grip issues.”